Mandrake wrote:Kai Burton wrote:older guy, around 50, balding, tracksuit bottoms, t-shirt, trainers

That's the image which sprang immediately to mind!
That.... what IS that?! Because of the scouse accent you mentioned I was imagining more like the "Scouse b******s" from Harry Enfield and Chums.
I once did Crazy Man's Handcuffs for a friend as we stood at the bar and the guy next to me instantly declares he can do it better than me (I love rubber band magic, Im pretty good at that trick), saying "Oh that's c*** (not the best), here let me show you how its done!". I don't think he was really a magician, just one of "those" types who like to know-it-all. He takes the bands, tries some elaborate loop system which was really blatantly not going to work. Anyone who knows Crazy Man's knows you don't need to do anything like this. Not remotely.
The he swore, tried again, and the band flicked out and hit the bar girl in the face. Thankfully it didn't hurt her, just startled her, but he was done for the night after that.
I generally don't bother taking them down a peg or anything, in this case I didn't have to either. Nobody really gives a hoot about magic if the guy (or girl) doing it is an a-hole.
It was tremendously funny to see him skulk off though.