Hi Everyone,
For protected batteries do you need to take any special care with them? Or are they just as reliable as the battery in your laptop or cell phone? Ie. Do I need to worry about them bursting into flames? 
Should I buy a fireproof bag to store them, or is that just overkill?
you should have a plastic box to hold the spare batteries when you get off it from charging room on devterm. take the batteries in the devterm or with a plasric holder.
Well protected or not, like any type of battery it ie better to store them somewhere where you cannot shortcut them, even if they have protection it is still not a good idea.
Lithium battery do not burst into flame by themselves just by standing, there are two things that can trigger that:
1 - sudden uncontrolled discharge like a short circuit (and that’s why a protected battery is better)
2 - Overcharging which is also something the protection in a battery try to avoid.
The 3rd that does not apply here are piercing a battery, at least not as easily as a pouch LiPo battery.
Just for information about crushing/piercing a lithium battery, they are the most dangerous when they are fully charged. They still can be dangerous when discharged, but less likely to go thermonuclear.
I’ve been moving old phones and batteries into the workshop after my wife’s cellphone swelled up like a balloon. I think 99% of the time these sealed protected cells (like the 18650) are pretty safe when stored, especially compared to lipo cell phone packs. But I also sleep better knowing where all my cells are stored.
I use a bag I bought for RC plane battery packs. They aren’t very expensive and have a nice big warning on them so someone doesn’t accidentally throw it away.