Some of this (players in teams at a "lower" level than they usually play at) may be caused by the wording of rule 3.7, which I just read again this morning.
"In each season players can move as many times as they want inside their own category. Out of their category players can move up or down as many times as they want. If a player has moved down once, he cannot move up again during this season."
So what the f*** does this exactly mean? You can move "up or down as many times as they want" OUTSIDE your category, but if you've moved down, you can't move up. Seems a bit contradictory to me. You can't move UP OR DOWN as often as you want if you can't move up again once you've moved down!
I'm sort of assuming that if someone plays at Am A then guests for an Am B team, they can't move back up to Am A (a question I was asked just this morning, which is why I re-read the rule). It seems a bit the wrong way round to me - I would have thought moving DOWN as the season progresses would be more of a sandbagging situation that moving back UP, and leaves things open for Pros who's teams aren't in with a shout for the overall title, to rip it up in the lower divisions.
Anyway, if anyone can answer my friend's specific query about guesting for an Am B team then back up playing in Am A for his usual team, I'd be grateful.