Then you need to have a talk with Mr. Darkleer. Not yell at him, per say, just sit him down and discuss things to try and get an understanding. He may have forgotten, but it does seem more likely that he had a reason. Do think about it and understand before reacting too strongly.

As for what to do with the Summoner... well. I would only lightly scold him, myself - I'm sure he's had punishment enough, with what he's gone through.