Nah... Lipo's are fine.
Although I did have one vent and bulge on me randomly and I just tossed it in some snow, nothing more came of it. I don't know if I have the picture anymore though, I'm on vacation at the moment.
Also yes don't empty it. It needs a minimum voltage to be able to charge back up (although there are tricks you can do with smart chargers like "jump starting" it on NiMH mode for a minute to get it to that voltage then balance charging it the rest of the way). You'll be able to tell if you're running it down though, there's a marked difference when the voltage starts to drop and that's when you know to switch out batteries.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE