Aka the 'blinkies'.
I frequently use these to judge how much exposure compensation I need to dial-in in order to minimise blown highlights on a subject (i.e. I dial-in negative compensation until I can get rid of the blinkies, at least in the section of the image that I'm bothered about).
However, I've noticed that when I actually get the RAW into DPP, I can usually undo whatever compensation I've applied without triggering DPP's highlight alert.
I'm shooting RAW only, but I think the camera still generates a JPEG for display purposes and to embed in the RAW. Is this correct? If so, is the camera's histogram based on the JPEG or the RAW? That might explain why the camera thinks the highlights are clipped when in fact they're not.