Garters are harmless...
The problem is a species of Keelback snake from Indonesia is in fact a rear fang snake (like hognose are) and are called "Indonesian Garter Snakes"
However they are NOT thamnophis, they simply call them "Indonesian Garter Snakes" because of the markings. The proper scientific term is Natrix vittata .
They are rear fanged colubrids but their bite is not dangerous to humans like many rear fanged colubrids. The bite is a tiny bit more painful than a bee sting and non-necrotic or damaging to humans.
however, most of them are wild caught and full of parasites.
Not too many people can keep them alive for very long either, yet the freaking importers keep on bringing more in.....