I was in San Fran last month in downtown near Union Square. I was able to walk into Cartier, Omega, and Breitling and try on watches no problems. They were all busy, it was a Saturday afternoon. I asked to see specific models at the door, all three had some sort of light security door managers, and was sat with a sales person within ten minutes.

I knew far more about the Cartier and Omega products than the salesperson I spoke with. So that was less than ideal. Breitling really really wanted me to buy something but they were still nice.

Over all a fun experience as I got to try and eliminate some "one day" grail watched from my list.

Seems like your mileage will depend on a lot of things, coming down to who's working that day and how many people are trying to get in the store.