McGregor's Celtic song prompted one fan - presumably Rangers-supporting - to throw their drink at the 29-year-old.
The UFC icon recently revealed he would have been fined $10m if he had been disqualified in his Las Vegas bout with Floyd Mayweather earlier this summer.
"Here's when I knew I was up against it: The ref was like, even if I lift my leg up, it's a point deduction. I'm like, "How is that a point deduction without even a warning?" he said during his appearance at the Glasgow event.
"So they're telling me they're going to deduct points straight off the bat. And if I do get disqualified for any reason, it was a $10million fine. Ten million f***ing dollars."
McGregor is expected to return to the octagon for his next competitive bout, with a third rematch against Nate Diaz rumoured to be in the offing.