This question is from Magic Game Day this evening, a Standard constructed event.
Player A had 
Liliana of the Veil on the battlefield and activated her second ability targeting player B.  Player B controlled only a 
Restoration Angel at the time.  In response to Liliana's ability, player B cast 
Selesnya Charm with its third mode.  And then player B paused.  With no verbage from player A, he resolved the charm and sacrificed the knight when Liliana's ability resolved.  At this point, player A cast 
Psychic Strike, targeting the charm (or some other instant that could cancel the charm).
I let it happen, but added a verbal caution that player A should have played the counterspell after player B cast the charm.  With regards to communication and shortcuts, player A hadn't actually *said* anything that indicated he passed priority, but I felt player B did leave ample time for A to respond.  And there's the weirdness that player A only cast the counterspell after seeing what B was planning to do with it.
Did I handle this correctly?