which can really bite you if you forget to Edit > Autosave as I just did. Can this be set to default to on in the enviroment variables, etc.?

You need to modify / create a 456.py in your scripts folder:

https://www.sidefx.com/forum/topic/12971/ [sidefx.com]

http://forums.odforce.net/topic/22589-default-autosave/ [forums.odforce.net]

This seriously should be a check box in the options at least.

Wow, yeah. This should at least be a preference, so that it's persistent across sessions, (though preferences still need to be updated every major version). Can you submit an RFE for it?

I didn't even know the option existed, and like most, I have seen quite a few cases where it would have been very useful.