The screen is so hard that any scratch is obviously abuse.
I have not only never used a screen protector, I've never used a case. My iPhone lives happily either in my business shirt pocket (with a pen and bluetooth headset), or in my pocket with keys. I've dropped it a hundred times.
My wife has my original 2G now, pushing 3 years old. It has 2 small scratches you can see, and 1 tiny one that only under certain lighting you might see if you know where to look. One came from being dropped face down onto a tine in my dishwasher from about 3 feet. The other i STEPPED ON IT face down on CONCRETE, in the rain when running, after it fell out of my pocket. If it takes THAT kind of abuse to get a single scratch on the glass, that's enough to not need the protector, which comes with multiple negatives.
My 3GS, which I've had since a few weeks after launch, is pristine. Yes, there's a few dings around the rim, and some micro-scratches in the plastic casing, but the screen is perfect, and it lives with my keys all day. no case, no protector, no problem.
...and you can buy screen protectors ANYWHERE. Apple is not banning them, they're just not carrying them online. Why?
- too costly to stock for tiny profits
- no perceivable impact to customers
- ridiculous pricing for a thin plastic film (should be $5 for a 10 pack, like it was a few years ago, not $7 for a single protector)
- negatively impacts usability
- numerous returns.
Apple DISCUSSED THIS with the vendors in advance. This was not an order, this was the result of planned action.