Yes, and if someone wants to spoil the surprise for themselves and not others, what's that to anyone else? Perhaps they enjoy the game for other reasons than being surprised.
As well, is someone who makes a choice to, for example, search behind the fireplace or the walls of a pit necessarily spoiling a surprise? It may not be a surprise for them that something may be there, but may be for others who don't have that knowledge. Besides, it's an action that someone without that knowledge can take. Would a player without the knowledge of the fireplace or the pit be spoiling a surprise by searching them?