I didn't use anything for protection, then one day at the track I saw a genuine LiPo fire during a charge. It was awful. It took out a table and looked for a short time like it was going to be much worse. It changed me, from that day forward I've used the RE Sack (pictured in the first post of this thread) I also store my LiPos in a fireproof safe when in my house. In my head I know that the really bad things happen when they are overcharged but having seen how unbelievably flammable they are, I have to use protection. Of course I use the right kind of charger on the right settings.

I don't doubt that they are safe and that other batteries also have risks but I'd rather be safe than sorry.