Doubt it, it's a rather tiny hole in the corner. It might lower his temps by about .001c or so. And like you said, it could pop off.
Wait...or do you mean completely filling the inside of the IHS? I'm thinking it'd have to be vacuum sealed (or air would still expand), but it's an interesting thought.
<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!