Posting content from paysites

Do paysites somehow tag a video with the member information of who downloaded it? For example, do they ever append member information to the end of the file, or put it in a video containers' information fields? Or even something more tricky like encoding "blocks" on a black screen?

How do people who post content from paysites deal with this issue? Do they just trust the paysite does not do that, or do they strip the information using some tool? Or even re-encode the video?

My initial guess would be that re-encoding the video is safest, but then how would one deal with issues of loss of quality? Or increasing the file size to keep the quality?

As far as I know, most paysites don't tag anything.

kk thanks. i will start a thread soon