> if its desirable for front facing cameras then perhaps disabling it for back facing camera is an acceptable compromise
That's already the case. The problem is that Snapshot/Aperture needs to know whether a camera is front or back facing. As said above that works for libcamera devices - i.e. on most other mobilelinux devices that already have camera support - but not yet for V4L2 ones.
Therefore my question about how you expose your cameras :)