It's the same thing, really. They pay you for eight hours but continue to own you for the next 16 hours. They pay you for two years but continue to own you for the next two years after they no longer pay you.

Yes. I had one company try to get me to sign a non-compete that would have ensured I couldn't get a job in my field for two years unless I moved across the country. I countered that I would sign that, if and only if (a) I was paid a two-year salary equivalent bonus on hiring, and (b) my offer was tripled since they expected to own everything I created 24/7. They backed down from requiring the noncompete.