A more thorough explanation:

Unfair surprise is a situation where one party is caught off guard by something unexpected that they had no prior knowledge of. This can happen in a legal setting, during negotiations, or in any situation where one party is not given adequate notice of something that could affect the outcome of the situation.

Here are some examples of unfair surprise:

• A lawyer presents new evidence in court that the other side had no knowledge of, giving them no time to prepare a response.
• During a business negotiation, one party suddenly changes the terms of the agreement without warning, leaving the other party unprepared to respond.
• In a game, one player suddenly uses a move or strategy that the other player had no knowledge of, giving them an unfair advantage.

These examples illustrate how unfair surprise can happen in a variety of situations and can have a significant impact on the outcome. It is important to give all parties involved adequate notice and information so that they can prepare and respond appropriately.