Michael pointed out to me in a private message that my replies here maybe consider dismissive and rude concerning the summoning issue. He also obviated the need for us to discuss it further, but I felt others may share his point of view and I thought this might a good moment to explain my logic, and that some may find my logic of some use to them.
When gaming, particularly con gaming, I practice what I consider to be, responsible table etiquette. Which is to say, I agree with sitting GM's ruling. Always. Even and Particularly when I know the GM made the wrong call, and yes if you're interested I have lost characters and even had a TPK as result of this. After the Game is over, I may talk to the GM and point out the rule, get his/her thoughts and logic. If I can't understand or agree then I may choose to skip that table in future, but that rarely happens.
To me this was case where a sitting GM made a perfectly reasonable call, so I support that call. For the same reasons I practice table etiquette b/c the GM's job is hard, should and must be supported. Now if I was talking with the GM I might have different suggestions to make. But that's a different question and set circumstances.
Now on the forums I love arguing about rules to me it's a lot of fun. I'm sure this concept isn't new to any of our regulars but maybe some home viewers will gain something from it.