Lol exposed battery terminals and keys are a terrible combo. Because I know someone's going to go nuts over this: This will happen with ANY battery. If you want proof, go grab some AA batteries out of the kitchen drawer and touch both side with your keys.So over the weekend, I had a Grasshopper battery in my pocket - my @Ratchett battery holder (which is awesome) was full so I couldn't fit this battery in it. I also had my keys in that same pocket (keys+unprotected battery=bad). It began to short out - it got hot enough before I got the keys and battery out my pocket that the wrapper on the batter melted, and I'm REALLY lucky that it didn't blow up or catch on fire in my pocket (it was close to it!).
This is no fault other than my own (and I've already ordered additional battery holders) but I wanted to share - I would make sure if you are carrying these batteries around you have them protected!
Disclaimer: Don't actually try this. It's one thing if it happens by accident but it's incredibly stupid if you do it on purpose.