I have seen a GP3700 do it a while ago, i saw one go in a touring car once also, there was very little left
We do everything we shouldnt do to these cells, things are bound to happen. Its just the way it is, there is nothing we can do really to maintain peoples safety, as the manufactures will insist they are being abused. Its down to the user to bear safety in mind, ie point it at a mate
But on a serious note charging them in a box is probably the best way as long as there is sufficient airflow. But not enough to cool the cell as it charges.