If you are talking about the internet then I agree. People can say and pretend to be anyone they like. Don't add people as friends until you get to know them. In real life, I say rely on what your gut instinct tells you about a person.

I believe that we should trust "A good deed is never lost"...if we trust someone and doing good for them then according to me goodness will return in one way or other..

not most people's hands anyway

Trust them with what? If you are that dependent then the problem is with you, not them.

You know, human being is not such a predictable species, airplanes crash once in a while. So, trust, as an absolute, you ought to take it a little easier, see it in a relative sense.