I have never drilled a stat myself. I figured if getting airbound was a hugh deal the stat manufacturers would drill it when they build it. Not saying its a bad idea but I have personally never had a issue with any older (pre 1990) engines getting airbound. I have on the otherhand gotten plenty of junk cheap stats out of the box. I started using Stant Superstats exclusively and never had a issue. I have noticed some rice burner stats have a hole with a checkball staked into it and I assume its probably a air bleed of some sort.
