mikeywith is trustworthy
I'm cherry-picking this part of your post, because I think this is the wrong reason to add someone to your Trust list.
I believe this is the correct use of the Trust system:
Don't confuse your Trust list with feedback
Trust feedback: leave feedback to people you trust or don't trust. Or leave neutral comments.
Trust list: a list of people who's judgement on others you trust (username) or don't trust (~username).
So if you think mikeywith is trustworthy, leave him positive feedback.
I can think of
other reasons to include him in your Trust list, just not this one.