Exactly. The other day I was carrying 2 relatively heavy boxes (furniture; I just moved into a new place) and suddenly a guy comes up to me and asks if he can help me. At first I was kind of flabbergasted, but after a second I was like 'he's just trying to be nice' and gave him one of the boxes. We carried it until we arrived at my apartment complex and had a nice chat along the way. When we arrived we exchanged numbers, since I learned he was new in the city and looking to meet new people and improve his language skills.
If my mum knew about this she'd probably think I'm crazy, being afraid of someone running off with her stuff. But in the end I think "trust-by-default" is a good way of going about life and meeting new people. Also, there's still gut-feeling. Maybe I'm an outlier there but I'm pretty quick in determining if someone is being sincere or just sweet-talking me to get what he/she wants.