A "warming sensation" is not what the OP has experienced.

When Bose augments this to the following, you may have a point:

>Remove headphones immediately if they spontaneously ignite and start emanating smoke and hazardous chemicals that cause chemical burns to your skin. Failure to do so may result in death. Rinse all exposed skin with running cold water immediately, and see a medical professional ASAP in such case.

You seem to have no problem with this scenario actually happening to someone, so there should be absolutely no reason not to have it in the same manual in these exact words.