Whilst I do think that it's a good idea to give people the benefit of the doubt, it's also worth remembering that in some instances the warning is entirely justified and comes from someone genuinely trying to protect you... proceed with caution if interacting with people you've been warned about.

There are people in Nottingham that I have "warned" people about, I don't expect my friends to keep away from these people, just be on high alert I suppose!

I do agree that we've all done stupid/shitty stuff, I know I have... there are some actions I have taken that I would not like to be judged by! However, there are also some people who are just generally nasty/dangerous/annoying for some reason, and are to be avoided!

I try to mention people's good traits along with the bad.