I work in an outstation, so we are cross-trained. When I am at the ticket counter, I refuse to give out standby passes to anyone unless I know I can fit everyone for the rest of the day on that one plane. I have been in the position too many times of having to take away boarding passes from standbys, both rev and non when another agent has prematurely given out the passes. (due to weight restrictions, cancellations, etc., not because I'm a mean person. ) Most of the rev passengers I've had to take bps away from were never really informed they were on standby anyway, they thought they had been confirmed on the earlier flight, because they were offered an earlier flight and the standby process wasn't explained properly.

I actually had a supervisor hand out two bps to a couple of non revs almost an hour prior to departure. When I got to the gate to work the flight, they were numbers 14&15 and I would have had to deny boarding to an elite passenger who the same supervisor put on the list at the last minute, when he knew there were 13 seats open. Thankfully, the nonrevs were gracious, but I felt absolutely horrible.

Also, with positive space, it shouldn't matter what the reason for positive space, at that point, it is the passenger's option to volunteer, they should not be forced, or that's the way I understand it.