So I told them if I ever had to take them in and put them up in our spare bedroom, they'd discover my welcome present would be having Pox Noise removed from my cable package.

The best I've ever done is illicit the pansy-ass retort "well… I don't know…"

Which is usually what they say when they have nothing else to say or can't rebut my argument or don't feel like arguing any longer. Because they've tired of me, or the argument, or both, I guess. So then I simply smile and chuckle and say "well, THAT'S certainly true!"