Thanks Stinger. Prevailing circumstances at the time didn't allow me to do that, but I have since done so and all worked fine.
Meanwhile I had contacted Bodner Tech Support to see what they had to say, and they basically said the same thing - plug in and see if it works! I can definitely see why they would recommend not enlarging the holes. A regular twist drill wants to catch the edge of the material which could snap off the corner of the board or perhaps crack inward. That's in addition to possibly drilling into the circuit traces. They said it depended on the size of the hole. Sure it does. But you're pretty close to the corner anyway, you couldn't enlarge it very much.
I carefully worked it out by hand to 1/8" to accommodate a #4 machine screw, and got by with it. I'm sure others have likely done this, never having noticed the warning on the Bodner website. My boards were the BBI-32 button board and the BU0836 joystick and matrix button board.
I'm sure it's best if you just don't do it, but with extreme caution and going slowly and carefully, it can work. And if you brick your board, I'm sure Bodner doesn't want to hear from you! :-)
