Metal people are cool. In 2014 I went on Motörhead's Motörboat cruise. It (as one would imagine) am absolutely blast with ~13-15 bands playing for the 4 days.
I had lunch with a fellow who worked for the promoter later in the cruise and he said security was bored to tears with the only "infractions" being telling people not to mosh. After all, we were on a ship at sea and there was no urgent medical care in case of an accident, so that rule held well. Also the staff loved us because we were tipping well.
Apparently when boarding the crew were a bit freaked out at the look of the crowd, but soon realized we were cool. Apparently there was also a booze sale record that cruise.