ccmann,
That's what the inspectors think out my way (Sacramento, California). That's the only thing they'll accept for labelling breaker spaces in panels. I can't argue, just about any stick-on label will eventually fall off.
I carry a bottle of some stuff called "contractors cleaner", a citrus-based solvent. A little on a rag will take off the remnants of a paper label if you're re-labelling a breaker space, or will remove the magic marker if you goofed and have to change a label.
Cliff
