After reading a little bit of the REG, Praeceps is correct. To clarify a bit, interrupting the ability doesn't undo the beginning of the activation. For an enhancement to be considered played, it's special ability must ATTEMPT to activate. It has done this, and since the interrupt doesn't stop the beginning of the activation, which is declaring the targets.
I have another related question. Can an ongoing triggered ability be inserted into SI if it is activated in SI after the ability causing SI is interrupted? The REG states:
"While triggered abilities are triggered by a condition or situation happening, they may not insert
themselves between other abilities to resolve. Instead, they are pending until all other abilities
resolve, and then the triggered event may activate.
Pending abilities are special abilities that have not yet activated because other special abilities
are taking place, but will activate when those other special abilities complete. Abilities that
are targeted by an interrupt ability become pending abilities that must wait for any abilities
associated with the interrupt ability complete."
So according to this, triggers wait for all other abilities to complete and interrupted abilities wait for all abilities associated with the interrupt to complete. So if the trigger is associated with the interrupt, which activates first?
