Good... let's hope he knows what he is talking about then ;-))
Sorry, did not intend to scare you, was only trying to highlight that power feeds to outbuildings can have some non obvious complexities that many people would never give a second thought to. Alas "add external socket" kits only make this more of a problem rather than less if they don't have adequate instructions.
The fact that you stopped and thought about it, already puts you into the "far safer than the majority" camp anyway. So carry on like that and you ought to get on just fine!
You can mention it, just choose the words round it carefully! ;-)