With the 10.7.3 update apple has “fixed” the non-local-HFS save issue. I say fixed in quotes since they haven’t really fixed it but they did make it manageable now.
Recap of the problem: Basically if you open a file on a non-local-HFS volume (i.e. a file server or SD card), your Autosave/Versions aware application would automatically save your changes without storing a previous version, thus erasing your original content. In 10.7.2 they added a dialog box warning you they were about to erase your content, but still didn’t give you any (easy) way around it.
New in 10.7.3: There is a new option in that previously oh-so-unhelpful dialog box called Revert. Clicking this button will revert to the original and then close the window for you. Know what that sounds like? Sounds like the Don’t Save button we have been trained to use for 20+ years. I give Apple credit for trying something new, but I applaud them for listening to the masses of people complaining about this new feature.
It should be noted that the Do not show this message again checkbox only works when you click the OK button. Turning on that checkbox and clicking Revert ignores that checkbox and the dialog will come up again next time.
It isn’t a 100% perfect solution, but teaching people that “Revert” means “Don’t Save” is far easier than teaching people to learn how to follow a new 6 step process to close a file without saving it and losing your original content. Thank you Apple for listening!