In fact it is the inherent strength of the lights that results in such violent explosions when the happen. The strength allows a massive pressure to build up before catastrophic failure.
Li-ions are really not as unsafe as you might think reading this forum. Think of the number of aircraft crashes and car crashes that are reported and how many journeys are made. The actual number of problems are very small and require quite serious abuse of the cells.
Leaving cells in chargers unattended and overnight can result in serious overcharging and then using those cells in multi cell lights and leaving the light on until the cells are dead and effectively short circuited is asking for trouble.
If you monitor your cells voltage before and after charging and make sure you use similar age/condition cells in a multi cell light and if using unprotected cells, stop using the light when it starts to drop in output, you should be fine.
I have been using cheap fleabay chinese cells, ultrafire cells and top of the range AWs for years and haven't had any trouble. I've discarded cells based on their voltage before charging and their holding voltage after charging. I've even put four unprotected cells in series in an incan and run it until it dimmed. One or two cells felt warm to the touch, and after checking them with a volt meter found they were fine. Li-ions actually perform better when warm, so can take a bit of heat.