i haven't noticed that webmasters are any less trustworthy than any other group of people. on the other hand, trust should be based on prior experiences with any person. once you have a fair sized history with someone, you can see if they've been acting in a way you consider trustworthy.

even so, a contract couldn't hurt.

when i try Dzinerbear's version of trial and error, i make sure in the early parts of a relationship that the things i trust the webmaster with are smaller things. that way, if they do mess up or not do what they said they would, i'm not totally screwed.

when it comes to letting someone install something, i go with many references from people i do and don't know and then i talk to the person who would be doing the actual install. i know over 100 people with strongbox and i also talked to ray who personally installed it for us.