The polyamory reference is in regards to the idea why the guy said "So?" was because he figured that Jen was poly and therefore it didn't matter if her husband was around or would be upset by his antics.

I've also seen poly used as an excuse for behaving poorly at other conventions, where the person assumed that A) the person they were behaving badly to was poly and B) that, whether or not they were poly, because they assumed they were that somehow made it OK to behave badly.