Last night, at my LGS's weekly Modern tournament, I ran into a situation. Anthony was playing Mono Blue Tron. He played and activatedMindslaver taking control of Nick on his next turn. Nick controlled two Young Pyromancer. Anthony proceeded to take control of Nick playing a couple of instants. The question that came up was this: who is responsible for announcing the Pyromancer triggers? I ruled that it was still Nick's responsibility since he controlled Young Pyromancer with Anthony only controlling Nick, not Nick's cards. I'm not sure if this correct.

Edited to get autocard correctly working.

Edited Darrin Sisneros (May 15, 2014 10:29:06 AM)

That's right. Anthony's control over Nick just means he gets to tell Nick what to do and how to do it. Nick still controls all his stuff. Anthony can't make Nick miss his own triggers, because that's not a legal decision for a player to make.