I have multiple DMs, whom I trust to one degree or another on various issues.
More than one of my DMs is a little shaky on the rules, particularly those that don't come up that often... So. Sometimes I am unsure whether or not the DM will make a correct rules decision (or interpretation that I agree with, in some cases). Oftentimes, I will pre-empt such a rules decision by bringing it up outside the game. For example, if I am planning on playing a tripper, but I don't know for sure if my Dm understands the tripping rules, I'll go over tripping with him to make sure he gets it... Other times, I'll avoid the rules in question. For example, if I suspect that my DM has a different idea on how paladins should behave than I do, I just won't play one in the games that he runs.
One of my DMs is a heavy plotter... That is, he tends to think of the 'story' before he thinks of the characters. So... I don't trust him to make a lot of room for the characters to make meaningful decisions. I do, however, trust him to have an imaginitive and engaging storyline.
One of my DMs has no sense of encounter balance... That is, I do not trust him to present us with encounters that are even remotely balanced to our characters' abilities. At least once per adventure (if not per session) I know that we sill be set upon by a squad of assassins that is twice our level, or something equally ridiculous. So... I min/max my characters for his campaigns heavily. And... most of the time, I play only at about half strength. That is, I use weaker attacks or keep my higher level spells in reserve, or whatever... And then when the inevitable ninja squad jumps out at us, I pull out all of the stops to allow the characters to survive, if not emerge victorious from, the encounter.
One of my DMs has a... flawed decision-making paradigm. That is, he sometimes makes very poor decisions. So, I sometimes advise the DM when I feel that he is about to make a bad decision.
Of course, it might sound like I am a know-it-all jerk who always has to get his way, but I am fairly certain that is not the case. It might also baffle some of you that I can play in a game with a DM who I clearly don't trust. But really, these quirks or imperfections that my DMs have don't bother me at all, and it makes their games unique and memorable... So, really, why wouldn't I play with them?
To sum up... No. I don't trust my DM, I know him.
Later
silver