the simple fact that there are videos on youtube that have shown what happens is enough reason to take reasonable precautions. It doesn't mean go overboard with safety measures (though you can if you want). Built in mechanisms can fail, so have a backup or two. There's plenty of YT videos that show all you need is a non flammable box like a metal tool box that can contain a lipo fire.
For every bad video of some retard putting a hammer through a lipo or charging directly from a power source to intentionally blow one up, there's a video of prudent practices for what you can use or do in the case of catastrophic failure.