grammatical number - Proper usage of "is" and "are" when specifying multiple nouns

This is one thing I never really bothered looking into, but have always been unsure of.

punching, kicking, slapping or slashing [is/are] strictly prohibited

That's what I'm trying to determine. Let's say multiple of these specified actions can occur simultaneously. Is it proper to use "is" or "are"?

This is going to be used in a short legal notice.