I had the same experience looking at a demo suite for a new condo complex (still under construction) across from where I was renting. I was in NO WAY in a position to buy, but I was just trying to get an idea what was out there so that perhaps a few years down the road when I might be in a position to buy I'd have some idea what to expect.
I walked in and was greeted by someone, and explained all this: I am not in a position to buy, I'm just getting an idea what's out there. I was asked "how many bedrooms are you looking for" "what's your price range" and so forth. I have no price range! I have no money! I'm seeing what the prices ARE! (like I already told you). I stopped just short of telling them they were wasting their time on me. As I walked around, I was hovered over, and I couldn't just look; every feature was explained to me and followup questions were asked. Finally they tried to get me to walk out with a load of glossy flyers and specs. No!! I was actually taking a break from de-cluttering when I went to look. I do NOT want to walk out with more glossy flyers!!
So, lots of good suggestions here. Like telling them outright that you would like to look without distractions, and walking out if that isn't allowed to happen.