For all the report type ops:

Spy
Spy On Alliances
Market Spy
Military Spy

There is a chance you "capture" their spy and get the op on them instead. It makes since that if you block their spy you capture them and get the info from them. If someone was spying on you it is most likely so they can attack you so this would add a bit more risk for failing spy ops other than just losing spies.

Waterboarding! Lol, I like it. Half the people I spy is to hit their allies though.

I don't know if a spy would have all the operations details on his own country's military, seems like the wrong person to send if they did.