Hmm... well, cutlines are essentially drivable if you have a good off-road vehicle, like a Lada Niva. And sometimes they are also used as tracks, but in forestry, these strips are created to separate forest blocks. However, cutline=firebreak is plowed every year to limit the spread of fire through the undergrowth, and they are not intended for movement. I think it's correct to show them as cutline=firebreak even if they are sometimes used as tracks.

It's possible that cutline=border could be indicated together with highway=track (if feasible) in cases where they are also used for transport.