Not a response to the specifics of this situation, but in general in regards to playing an A player down.
1. In Europe, it is common for A team players who are not getting playing time, or who are coming back from injury, to play with the reserves in the reserve of B team match.
2. At HS, I once had a freshman on varsity. He had been struggling with the size/force/speed of HS varsity 4A play, and then gotten an injury. When he was fit to play, I played him on the "C" team, just about all freshmen. (He was a 9th grader). This was about midseason, and the kid had scored about 2 goals on varsity. I told the kid that this was a "rehab" game for him, and it was a fitness test. The C team played on a different night than the JV and Varsity teams, so it was a conveniet fit, it would not take him out of being eligible for the next varsity game.
3. The kid scored a hat trick in the C team game, which did wonders for his confidence. He played with the varsity for the rest of the season, and played better than he had before he missed time with his injury. However, the opponents (Walla Walla HS) complained about him being played on the C team and were very pissed off. (Of course, it had nothing to do with their 9-0 loss, at home........).
4. The AD at the school I was coaching at, also recieved a complaint from the parent of the freshman that I had given the rehab assignment to. "How dare the coach demean the player like that, when he was so good, obviously the best player on varsity on the attack, etc. etc. etc.) The AD decided, before talking to me, that what had happened was wrong. The AD is going to be (most likely) the next superindendent of the Kennewick School District.
5. I believe that there is truly a major difference between A and B teams, and teams within the same club that are "Premier" (RCL/USCS/Whatever) and select. If a program is designated A/B/etc. then the lower designated teams have an absolute obligation to support the development and success of the higher designated teams. Including having guest players drop down upon them for "tune ups". That is the way things are set up, everyone should realise that (unless people are lieing to themselves or each other), and that is what is best for the success of the A team, which is the MISSION of that system.
If there is a definitive break between the "Premier" and the "Select" squads in a club, where the select team(s) are not designated the B or C or whatever lower ranking teams, then the mission of the select teams is different. The mission of the select teams becomes one of developing its own players to their best extent, to developing thei rown team as greatly as possible, and if - and only if - the select players want to move to a premier enviroment, are they then required to do so. In such an enviroment, while a select team might accept some outside players for summer tournaments, they would not be accepting Premier players dropping down in league play. It would take away not just the playing time from their own players, but it would be dishonest in what they are playing for, a league title.
6. As illustrated, it seems that it depends upon the way the club structures the enviroment, and the objectives of the teams involved, as to whether bringing an A team ringer down to the B team is acceptable. To me, it is very clear cut. If a team is playing for a reward (promotion, league championship, etc.) then bringing in a upper division player, even for rehab, is not acceptable. In HS, where the the JV and C teams are not playing for any title or standing, then things are vastly more relaxed. In Premier (RCL/USCS premier wannabe equivilient) bringing down an A team player for appropriate reasons is entirely appropriate, since the standings or success of the B team in Premier really does not matter. And no, a B team being promoted from the 4th RCL division to the 3rd does not really matter, in fact it can be seen as a detriment to the entire organization.