Well not all flakes are bad!!!
I meet people about 5 mins from where I live, that way if I do get a phone call about them being late or canceling then I usually haven't left the house yet, I just stay at home and wrench some bikes.
I think a key thing to do when your arranging to meet with someone is to get their phone number, I usually call them about 30 mins before we're supposed to meet and I ask them if they're still on schedule or where they are at. It's much more easier to cancel an email appointment then over the phone, i believe its just cause the transaction or meeting seem to have way more humanism overall. If they do cancel then at least they have your phone number, most of the time ppl call me on the cell if they gotta cancel or reschedule