I also think it's rude to sneak, even though some might argue that it's not illegal and that you have to sneak to get a good shot. I prefer to be open about it and people who don't want to sign anything usually don't want you to take their picture either. I was also a bit freaked out at first, but after a while it's no big deal. But of course you have to use your discretion, some common sense goes a long way.
Here's someone I met last weekend:
and here's my simplified version of the release he's signing:
MODEL AGREEMENT AND RELEASE
I hereby grant Anna Yu permission to photograph me. I further give my irrevocable consent to Anna Yu and her direct or indirect licensees and assignees to publish, republish or otherwise transmit the images of myself in any medium for all purposes throughout the world. I understand that the images may be altered or modified in any manner. I hereby waive any right that I may have to inspect and approve a finished product or the copy that may be used in connection with an image that the Photographer has taken of me, or the use to which it may be applied. I further release the Photographer and her direct or indirect licensees and assignees, from any claims for remuneration associated with any form of damage, foreseen or unforeseen, associated with the use of the images. I certify that I am at least 18 years of age and have the full legal capacity to execute this authorization.
name and address, etc follows.
Good luck with yours! Don't forget to bring a pen!
-Anna