It's a neat mod, but I'd be worried about the nub touching the screen when it was closed, and either damaging it though pressure, or wearing a shiny/dull patch into the screen.
I have a little visible patch on my T60 screen where one of the weird shaped ultranav caps rubbed up against it at some point (should never have used anything but the old fashioned one, even tho the one that caused it came directly from IBM as well).