You are very mistaken about the legality here. Probable cause only matters to law enforcement agents. It has no bearing on private citizens.

The private citizens rights to seize property, turn it over to LEOs, report someone, conduct a search, do not change if they have probable cause to believe a crime has been committed. So, if I'm your boss and can legally read your emails, I can just turn them over to the law enforcement agencies no question asked – they're "my" emails after all.