Some have said so but to be even more clear: Encounter powers have nothing to do with encounters. It's actually kind of a misnomer. "Powers with 5 minutes cool down" would be a more precise term.
So in this case the GM does not have to determine anything. In fact, pointing out that the GM can determine things is generally a rather meaningless answer when it comes to rules questions.
So in this case the GM does not have to determine anything. In fact, pointing out that the GM can determine things is generally a rather meaningless answer when it comes to rules questions.