What about for other similar products? Bike light batteries are a lot more likely to get abused than laptop batteries. Especially batteries that have no armor around them. It could be that the only real problem with them is that they weren't in a hard plastic shell, making them vulnerable to damage to the protection circuitry, or direct damage to cells, if dropped. 18650 cells, if impacted sharply on the top corners, short out and WILL burst into flames, period.

That could mean that it's a bad design decision to not put them in a protective case, but if it requires abuse to cause them to flame up, IMO that's something to take into consideration.

Risk is always a tradeoff. There's no such thing as a LiIon pack which can't possibly burst into flames. I kept my cells on a flameproof surface when charging and storing, as I do with all my larger capacity devices.