Can you opt out of flipping a Secret Action, even if it triggers? For example, if Infiltrate is on the field and your opponent plays an orange Action, could you choose not to negate it and hold Infiltrate's negate effect for -- hypothetically -- a second action that they use through other means?

Revealing Secret Actions is optional. A little while back, we had answered a question pertaining to this issue and said revealing Secret Actions was mandatory. After testing and reflecting on this internally, we’ve decided to reverse that decision. If additional game actions occur after the event that would have revealed the Secret Action, the player whose Secret Action it is will be considered to have elected not to reveal it. Note: This doesn’t mean you should play fast in order to try and trip your opponent up. If your opponent has played a Secret Action, you should give them a reasonable chance to reveal it.

Source: Wizards of the Coast (2019-06-28)    【Link to Ruling】

Tags: Secret Action