I used the original Droid for two years without a screen protector. Multiple drops, no carrying case, and the screen still looks brand new.
I've had my Bionic for three weeks and it has a shallow, but noticeable, scratch about an inch long. I always carry it in my front pocket by itself, just like my old Droid, and I've never dropped it, thrown it on a table, or set it down on its face.
This looks like an example of Motorola taking something that worked perfectly and "improving" it to the point of fault.
My guess is it's the "glare coating" I've read about. GG might be protected from scratches, but anything put on the outside of it will be scratch-able.