Giving out admin to people who act "good" is, well... let's say it's not a good thing to do.
For all we know they could just be "acting" good so they can get admin to do bad things.
My advice: Give out admin to friends that you very well trust and think that they're capable of holding a responsibility like that. Don't just give out admin to people who are "acting good". Oh and, NEVER host a free admin server. Those turn out... bad.