From the Higher Ed article:

“If I see anyone I know step on the American flag I will personally shove the flag of another country up their ass,” one Twitter user posted. Others have stated those standing on the flag should be “curb stomped” or have their necks snapped.

This is perhaps what Cumia refers to as incited behaviour. But it doesn’t have any relevance to what I guess he was making mention of originally: the Trump rallies.