It's actually quite rampant on the world I come from.

I'm a mage living in the only country that doesn't persecute mages...well mages with a fancy blood line anyway, but you're still safer there than anywhere else as a mage. Everywhere else mages are rounded up in towers and spend their entire lives there, many suffer abuses.

In certain societies mages are chained and leashed with their mouths sewn shut. All of this due to religious or philosophical partiality and fear. I've seen plenty of this nonsense and for the most part it stems from the actions of a few leading to the persecution of the many.