I know there are many reasons (though not hundreds) not to house snakes together, but I've been doing it quite successfully (don't even ask me to define this) for 10 years. For a variety of reasons, it works for our situation. Does this make me uninformed?
Not to mention, while I am a big fan of rubbermaid, I keep lots of snakes in aquariums, including ball pythons! At small sizes, rubbermaids are great, but when you're talking about 3'-4' long units, I don't find them especially useful or readily available.
Unquestionably though, I'll agree that garters aren't social! They might all be in the same hide, but it is because that location is the temperature they all want to be at the time.
If what we want didn't mean a damn thing, then why would we have reptiles in captivity in the first place? Wouldn't we just put all our resources into conserving them in the wild and seeing them there?
Oh, and although I don't use sand except for sand boas, I assume you are informed about Calci-Sand, which is calcium carbonate and is completely digestible???
One more time, for the record, I still like temperature gradients. But, I think you should back off a bit on your assessments of things people should or shouldn't do, and who is informed or not!