"Although I was very tired, and it was a night flight, I couldn't resist to do some basic security checks in the entertainment systems,"
While I do believe that identifying (and so remedying) security flaws is a good thing, why do security researchers and the like seem to think they have the right to just jump in to systems like this? And this certainly isn't the first time I've heard of someone probing around on live systems of an in-flight aircraft to see what might happen.
If I was a professional locksmith visiting a hotel, and started trying to pick the locks on other guests' room doors just to see how secure they are, I'm sure I'd very soon be having a conversation with the boys in blue.