Similar thing happened to me recently I had a private ops ferry flight to do and I put my uniform on with the intention of looking for work doing the meet and greet on the way. On my return I got a please explain from the local CASA foi because some body saw me pulling the aircraft out of the hangar in uniform and assumed I was doing charter work without an AOC. I know who it was and their advanced age is the only thing saving them from a kick in the balls. they could have rung me directly to find out what was going on with out wasteing casa's time or they could have minded their own business.