Most tube sites will remove your stolen content from their sites once you send them a copyright infringement notice.
When I visit those tube sites, I see loads of scenes ripped from porn movies, but only few scenes from paysites.
I see some rebranded stuff that low-life webmasters upload to boost their sites, but mostly it's amateur movies or scenes from porn DVDs.
You obviously can't stop tube sites to show amateur movies.
But why the DVD producers and companies don't react on their stolen movies being displayed on tube sites is beyond me. 
If only they would react, the tube sites would be bound to amateur content.