If the thing catching fire is totally innocuous, then perhaps you needn't characterize your device to such extent. However, if you have to perform a failure mode effects analysis, you'd best know what happens under what circumstances, regardless of whether the device has been abused.

The device may fail traumatically, and "legally", in the sense that you can say "I told you so ..." but that won't buy you much good will. If the device is above an exit door and "spritzensparken", thereby denying everyone use of that portal, things could go badly for you, even though you can blame someone else.

RE