A: Most Surprises specify a type of card or game action which it reacts to. This specification isn’t a permission so much as it is a restriction. Not having one doesn’t mean it has no permissions, it means it has no restrictions.

In other words, if there is no specific trigger listed, it means that the Surprise can react to ANY kind of play. Since there are so many possible game actions or card types one might want to use My Turn Next in response to, it doesn’t make sense to have to list all the times it CAN be used. Rather, it makes sense to simply not list a restriction at all. You can play it “in response to” ANY game action by another player. We’d like to be able to specifically call out this lack of restriction on the card, but space is very tight.

Some examples:
You might play it in reaction to a Hand Limit, so that you don’t have to discard it. You might play it in reaction to someone Trading Hands with you, so you get to use it instead of giving it away to them. You might play it because someone has played a Goal you need so that you can play your winning Keepers ASAP before someone changes the Goal to something else.