I've no bone to pick with Kenpo on this (the O/P), but I've heard other art's instructors, not only/just Kenpo, say that sortr of thing to their student body.
Fighting skills are, to a point, frangible and decrease with time. I would say that, once a person has practiced in something for 30 years, most of those fundamentals are now ingrained and part of the person and won't be forgotten. That's not to say that the physical ability wn't erode, but if they had to erupt into violent action, they could. Then, maybe they'd fall over from exhaustion, have a stroke, have fifteen muscle pulls and joint strains, etc.
But, to tell folks, "You are now Billy Bad-*** since we've awarded you the speckled hen certificate, waved the wand of Badjiju over your hands and feet, and given you that awesome magenta belt," it's a bad idea.