A card can collide with the area more than once; many of the campaign memory bags caused a double collision on placement, and it would happen if the user picked up or flipped the card.
This would cause any behavior that triggered from the event to each time, so suppress further events which don't actually change the scenario.
Based in the newly-named Mythos Area, when a Scenario card lands the name will be extracted and sent to interested objects.
Playarea will use this for special location handling, and there will be other cases in the future.