Outside the club is your own business. There is no legal reason you can't take pictures of people outside, but if you piss people off and they complain at the door, the doorman has no obligation to let you in, either. Use your own discretion there
To answer questions 1 & 2 there are posters with the guidelines up at every event that read:
Absolutely No Unauthorized Cameras Under Any Circumstances!The use of cameras and digital cameras is allowed ONLY by authorized personnel. If you wish to take pictures, you must clear it first with Sin City staff. Any pictures taken must be with the explicit verbal consent of anyone in the frame, and must not include any "accidental" people in the background. If these guidelines are not followed, camera privleges will be revoked! Respect the wishes of your fellow sinners!
If someone has taken a picture of you without your consent, please report it to a staff member immediately. Anyone taking unauthorized photos will be asked to clear or delete the film or images from their cameras and surrender their camera for the remainder of the evening. All decisions are final!
In summary, ask someone with a "Sin City Staff" card before taking pictures inside the club. Bar staff (especially at Richards) don't have the authority to allow pictures, but they will (especially at Richards) come down on you if they catch you taking pictures at which point if you don't have a Sin City staff member to point to and say "he said it was OK", you're up a creek without a paddle.
Sin City staff (me included) will usually say it is OK, as long as you aren't getting anyone in the picture who doesn't want to be in it, i.e. we'll give permission for taking pictures of friends up against the wall.
If you have been given permission there is no reason to wait until I'm done with the booth to take your own pictures, as long as you aren't holding up the people waiting to get a picture from me. I frequently let people take their own pictures in the booth while I am set up if I don't have a line or I'm going for a break (but expect to be shoo'd out when I get back).
If you've got permission and you're in some other part of the bar taking pictures (eg. out on the balcony at 23 West or upstairs at Richards) it's no skin of my nose. If you are standing right beside me and you are screwing up my shots and setting off my slave flash we'll play a game of "Ozzy" where you are the bat ;-)
Now, tangentially, I *won't* be set up at 23 West on for the May 12th event because I've got an out-of-town obligation. If you'd be interested in filling in for me and taking some photos for the site, come see me tomorrow at Richards and I can arrange it.