A nice solution is for the problem to work it self out. If both coaches are good sports then there is a legal way to sort it all out. It's done out of courtesy in other sports, why can't basketball be that way too. For example, I've heard that in soccer, it is not uncommon for a team to deliberately kick the ball out of bounds when the opponents have an injury. The opposing team returns the gesture of good sportsmanship by throwing the ball in to the team that kicked it out.
After team B scores the uncontested goal, stop the game, tell the coaches there is nothing you can do to fix your error but in the name of good sportsmanship B could fix it by allowing A to score uncontested and by throwing the ball in to A. The points would be effectively negated and A would have the ball. Propose it to the coaches and see what happens. It can't get any worse.
I suppose that you could call a T on coach B for unsportsmanlike conduct (similar to having the wrong player shoot a FT) by having his team deliberately take a throw-in that was not theirs. The 2 FTs could offset the points and A would get the ball back too. Again, all is evened out except that B's coach has a T which he deserves if he trys to win that way.
[Edited by Camron Rust on Oct 2nd, 2000 at 06:37 PM]