I also like to stop in and look at the merchandise at ADs, but unlike droptopman, I find it INCREDIBLY EASY to walk out without buying a watch. That's probably down to my incredible discipline and willpower, and nothing to do with my financial state...
However, I've never had a problem with taking photos of the watches. I usually ask permission, pull out the Canon, and start shooting. The only times I've been prevented from taking pictures were at various rep sellers around Asia.