That is a concern of mine as well. I've been researching this but haven't come up with any solid answers yet. As far as I can tell, some batteries have 'smarts' in them as a safety feature, but still aren't clear on what is safe and what is not (other than to used same brand and same voltage level batteries).
The thing is, never mix batteries/cells really, of different states of charge.
This applies to just about any cell/battery in anything, it's just more serious with lithium primaries.
Only use new cells in multi cell lights.
Depending where you buy them, they may be shrunk wrap in pairs to help avoid that.
On rechargeable cells, it's the same thing, don't mix various states of charge together, although rechargeable usually have electronic protection to help prevent, they can fail. So charge in pairs together, and do not separate them, they are married to that light or at least together.
So the best protection is yourself, do not mix drinks, then there's no throwing up volatile chemicals.
Hope it helps.☺