Trusting People

I think I maybe read too many stories where people get duped into losing their money, so when I had a random guy come up to me and strike up a conversation, immediately I put my hand over my pocket to make sure no one would steal my wallet.  

He told me that he was from Chiang Mai and he just in Bangkok doing research for his boss.  He was researching the different prices that foreigners and locals get quoted for transportation fares and tour packages.  He didn't seem all too harmful except ...
• he was a little too friendly and no one's been THAT friendly so far
• he was a high school teacher and what high school teacher does that kind of research?
• he kept telling me that I wouldn't have to buy anything ... only go into travel agencies and ask for a quote
• he tried really hard to get me to go with him
• he kept asking about how long I was here, when I got here, where I was going after ...

I think I was good not to trust him.  After all, I did read a bunch of stories telling meticulous watch out for shady people.