leave no trace
interesting reading at http://www.leavenotrace.org/. It seems that there are still more than a few people who either don't believe in or choose to ignore these guidelines.
In my mind, this stuff is common sense; It's about trash, it's about locals, it's about respect. In a very large way, it about the image of BASE jumping as a sport...and its participants.
Aside from the obvious things you will find on the website above, some other simple rules for BASE are:
Avoid being seen:.
This will help you to not get busted. It includes not jumping high profile/illegal sites during the day, among other things. Legal or not, it's always best if no one ever knew you were there.
respect/call the locals:
This has been discussed before--look it up. Think about YOUR local objects and how YOU would feel if some out-of-towner burned them.
Be a respectful local:
The flipside of the "call the local" rule, when you get the call from the out-of-towner, be a gracious host if you can.
Don't bring the media to illegal jumps:
They're whores. They're the antiBASE. It only takes one or two fucked up newscasts or ignorantly written articles to show BASE jumpers in a poor light. They lie right to your face to write what they want. There's a better path to the glory you seek.
be safe:
what difference does it make how stealthy you are if you go in? Break your leg? Your back? Your Neck?
be smart/know your limits:
BASE is evolving quickly. There are fewer and fewer black and white situations and more and more grey areas. One must make a multitude of choices, many of them weighing life or death options. Gear, prevailing conditions, people you train and/or jump with, knowing when to say NO (a Kenny Rogers song comes to mind here: maybe that's another reason they called Frank "The Gambler"!)
be polite:
What is so hard about this? I don't get it. I've actually tried it--people respond pretty well! It's understandable if you get busted and the cop is a dick to mouth off a bit...But at legal sites, whether you like it or not you, the person with a BASE rig on...are an ambassador of the sport--this is true if you are hiking up a trail to make your first jump or just landed your 6000th. Antisocial? a smile will usually suffice. Of course, if you happen to be jumping in NYC, if you're too nice they might suspect something, so just blend in

Anyone care to add anything?
mh