This varies from jurisdiction to jurisdiction but your observation could be correct as far as criminal cases are concerned but not those of civil nature. A deeper research would be required but my gut feeling is you can't produce illegally collected material as evidence in our case.
My personal observation is that deep down UEFA knows they dont have a strong case against us but are pursuing with it to make the elite happy or saving face. Even if they manage to get us banned, i am 100% convinced it would be overturned on appeal and thats why they are having second thoughts about banning us as they know on appeal we have a strong case in a netural setting and dont want to go through that humiliation.