I can't see a problem if there are TOO MANY choices for subs (coming from different members).
Mostly true, but sometimes BLs want to be able to negotiate fees w/ subs and they'll pick a good player who accepts a lowball offer, or they might have a player they've been looking for a chance to network with, or they might have had previous troubles with the sub the player picks. And, of course, some BLs are just control freaks.