I noticed that too.

On my N800 with a screen protector, I notice that the screen is still pretty responsive when using a stylus. However, finger swiping for things like kinetic scrolling feels a little awkward.

I wonder if it is the case that we are not going to get the true feel of the UI if we slap a protector on the screen. I would love to protect the screen from scratches with a protector (and I still intend on using the stylus a lot), but I am debating if this is the right thing to do since the UI involves a lot of finger swiping.