I suspect it's more to do with HOW the OP was being asked that WHAT he was being asked.
A few years ago I had a confrontation with a guy while waiting to pay at a grocery store. It was pretty busy. The guy pretty much pushed me aside from where I was standing (right by my stuff on the belt) while saying something like "excuse me please, would you mind moving over while I put some of my things on the belt"... even if the belt was fully occupied and there was no space until the cashier freed some more at the front. The thing is the guy said the right words, and even if there was no space for him I would have moved, of course. But he was rude about it, the words were unsincere with a tone to match, and he just fully expected that by saying 'please' then it would be ok to physically push me.
So I pushed back and loudly I said "no, if you wait another 15 seconds or so, you'll have plenty of room".
He didn't like it.
I'm generally pretty accommodating and courteous in most things in life. But some people are too self-centered and I guess they get used to everybody else just letting do whatever they want to. Some days I just shrug it off... "who cares" right? But some days it just brings the "f*** you" in me.
I suspect if the OP had been asked nicely this thread would have never existed, the OP would have let the people film, and he would have tried the amp a few min later, no problem. I find it fascinating that some people called him out for being bothered despite his being compliant. I would have loved to see some of those people's reactions if they were aproached in the same way the OP did.

We're all saints at the keyboard, eh?