Nope, I haven't drilled any holes in the cork except to put in hooks - then I discovered that if I used cup hooks, I could just screw them in by hand anyway. They usually end up hanging on just a slight angle so that no water ever pools on the cork.
I don't know if it makes much difference, but I don't usually re-pot or stress an orchid while it's in bloom. They blast buds on me often enough without giving them an excuse.
