Snakes are not meant to be pets. They are wild animals and should be remain in their native homes. This also includes any exotic animal.
One problem, if we release pet snakes they'll just become invasive species. So where will those ones all go? 
Anyways,
Pie > Cake
Take them back to their natural homes. If they're willing to go and tame them, then releasing shouldn't be a problem. But with human beings being lazy, then sadly I have no better solutions. The problem should have been avoided from the start.
