yep its not the best of ideas. you really have to establish trust...and like shdw said, from both sides. the bookie can be as irresponsible and as untrustworthy as any bettor... both parties have to be responsible.. honestly, it's only a matter of time until you run into a problem. In my very limited dealings with forum members i had a bad egg. it will happen
my biggest advice to any "bookie" is treat it like a business. don't keep putting your hand in the cookie jar. it's not free money. pay yourself once every quarter, 6 months or year.. and never go below you're certain bankroll number, which better be at least 5 figures.
i've had people win 15k in a matter of a month and that's with $500 limits.