If I'm going traveling, I'm sure as hell in "untrusting" mode since I don't have a clue what the locals are like.
There's strangers as in "local resident I see each day but don't know", and there's strangers as in "I've just traveled to a completely different country and have no clue who this person is"
Wanting to trust everyone and believing majority of people are good is a nice hippy dream. There's some nasty horrible people out there.