2) Wear a silent hip scarf! it can have as much fringe, beads, sequins, and bling as you want, so long as it doesn't make noise (or spray onto the floor and cut other student's feet). In workshops teachers are already trying very hard to find a balance between the music being loud enough for everyone to hear it, and quiet enough for everyone to hear their instruction, add a lot of coins or bells (which may or may not be on beat- see number 11) and it's just chaos.
Personally, I allow (and even loan out) hip scarves with coins in my beginner classes because they're fun and I also find them a great tool for learning shimmies and isolations, but workshops are not their place.
4) If you're going to take notes, which I do recommend, have them near by. (Check back sometime to see if I get around to patenting a note-holster for dancers ^_~) If you don't have a way to keep your note pad on you then find a spot near the back or side of the room, so you don't have to cross in front of people every time you want to write something down.
5) Leave extra time to find the venue. You might want to socialize before (not during), or you might want to shop before the workshop starts, either way you don't want to disrupt the workshop by being late. Since this is a new place you might not be able to find it right away, so give yourself some flexibility and avoid the stress.
If you are late, again, be as ninja-like as you can when you slip in. Find a spot in the back, and jump into the class. If you are late and your body needs a warm up it would be better to do it in the waiting area outside the workshop, again to not disrupt those already learning.
8) Speaking of taking care of your body during an active weekend, bring a water bottle. In most parts of Europe and the USA you should have a reusable bottle and refill from the tap. If you're going to be someplace where you're not sure if the water is potable, check. But for serious, do the planet a favor and get a reusable water bottle! (And then spend the money you saved on CDs ^_~)
9) The last point about taking care of your body is: see if you'll want to bring a seat. Some workshops have a lecture component, such as a lunch time panel, or even be 50+% lecture (such as the amazing Journey Through Egypt Series by Sahra Saeeda!) and in these cases you'll want to give your bum some cushion and/or your back some support. This isn't necessary for all workshops, so look at the description of what you're signing up for.
Teachers have a variety of reasons for not wanting to be filmed. They might not feel they performed at their best that day, and they are managing their brand. They might want to keep the choreography under wraps- so that it remains marketable, in which case filming and posting would be violating their copyright, or they might just be feeling bloated and not want to be on film. Either way they should be respected.
In terms of filming the rest of the class doing the choreography, at the end you may ask to film only those dancers who want to be filmed, and share it with only those in the workshop. Don't film the entire class without giving those who don't want to be filmed the chance to step out of the frame. Especially if there are minors in the workshop.
12) Along the same lines of trying another style: do it the teacher's way, unless it hurts. What I mean is that, unless you have an injury or the teacher is legitimately asking you to do something that will injure you ("go ahead and throw your head back as hard as you can! you don't need those vertebrae anyway!") then you should follow their instructions as best you can even if it's not how you or your teacher would do things. It's fun to try on their style, and besides, that's what you paid for, right?
13) Ask questions, respectfully. Your weekly class might be more informal and it may, or may not, be ok to just ask questions whenever the teacher isn't speaking the same way you would in normal conversation (this is closely related to class size, the bigger the class the more formality is need to ensure everyone can learn). In most workshops you'll want to raise your hand to ask a question or the teacher may indicate that they will answer questions at specific intervals, but you absolutely should ask! There is a good chance others either have the same question, or haven't even thought of it but would love to know.
Questions to clarify weight placement, muscle use, cultural significance, lyric translations, appropriate costuming, how a style/song/choreo fits into a set; are all common. If you are confused because the teacher seems to be doing something "wrong", ask in a gentle and open minded way for a clarification or to help you understand the context. Remember that there is a wide range of "right" answers, and this range gets even wider when you expand to new-to-you styles. Also, some teachers might convey a concept as the "right way" to do it, when they are just using short hand to simplify things for a beginner class. (We can debate this approach elsewhere ^_~)
I, personally, feel I get more out of the workshop when I think of the choreography as a tool that they instructor is using to teach me something (that is how I use them in my weekly classes) and focus on what that is, than if I am stressing out about remembering a specific chain of steps. That said, not all workshops teach a choreography (I never have used one is a workshop setting) and you should still be following along with the instructor's steps, technique, and other instructions.
As a bonus for this point, especially when you have native instructors who speak the language the songs are in: look at and imitate their faces just as much as their bodies. This will help you to get "the feeling".
15) Some dancers expect a type of row ranking. This is a system in which the most experienced dancers, or those most skilled at picking up and remembering choreography, are up front. There are good reasons for it: mostly that in very large workshops it may not be possible for everyone to see the instructor and those in the back are relying on the front row to pass the information along. I don't necessarily agree with this method and when I teach I prefer to rotate the lines so everyone can see, but this is an expectation at some workshops. If you are going to follow the advice in number 14, for sure situate yourself to the side or back.
Bonus: Clapping/thanking the workshop instructor at the end of the workshop is the norm. The group as a whole might clap and say thank you, and you might notice some individual students walking up to thank the instructor personally after. You might also have lingering questions to ask, and now is a good time if you can get in there.