FreeBSD unionfs

[probonopd]

The BUGS section in man mount_unionfs states:

THIS FILE SYSTEM TYPE IS NOT YET FULLY SUPPORTED (READ: IT DOESN'T WORK) AND USING IT MAY, IN FACT, DESTROY DATA ON YOUR SYSTEM. USE AT YOUR OWN RISK. BEWARE OF DOG. SLIPPERY WHEN WET. BATTERIES NOT INCLUDED.

Having a fully working, stable, tested unionfs in FreeBSD would allow the Live ISO experience to be much better, and with way less workaround-ish hackery.