But when you are dancing somebody could be filming and updating to YouTube so maybe you should dance accordingly.

I guess the point of that proverb is that even if you dance badly, you'll at most be ridiculed, but possibly become a hit. You will likely not be imprisoned.

(Well, in Western countries anyway... except if the dance contains hand movements or such that are illegal. I mean, if it's just a dance, no problem.)

Exactly, and once these sorts of videos become common enough in society that everyone has at least one, they won't even harm your chances at employment.

I don't know, some guy I am only 6 degrees separated from disagrees.