I can see where you're coming from. I was trying to think of the least "intrusive" way of doing it (without having to use adhesive or drill extra holes). I've used this method on very small holes in plastic cups within a tank, but if they were much larger I imagine it would be pretty easy to knock them out by accident.
I agree with stealthypotatoes method in that case, using a fine mesh and small drill holes would be best. Unless you were to try getting really tricky with a router.