I never heard that one before, I just always assumed it wasn't a good idea to bottom out a drill bit in any drill chuck. Learn something new everyday.
I probably still won't try it though. My keyless chucks have the holes for a spanner so it was easy to get it loose. Even since I got a drill bit stuck in one of my keyless chucks that's when I set out to get me a keyed chuck, to use for bigger drills & taps. Luckily I ended up with 3 made in Hartford 14Ns & an 18N.
I primarily use keyless chucks & like them, such a time saver, but I won't use them with S&D drills anymore unless I'm drilling non ferrous metals or mild steel.