Never really thought about it. Our frames aren't riddled with holes. maybe 4 or 5 in total, spread around the frame. The heavy gauge ERW tube we use has a wall thickness of nearly 4mm, so providing the holes aren't excessively big, I wouldn't have thought you'd have a problem. I keep any around the headstock a couple of inches away from the joints, as it's the most stressed part of the frame, but otherwise it's just common sense really. The SVA guys will want you to fit rubber grommets or plastic spiral wrap around the holes to prevent chaffing of the wires or cables & if you run copper brake pipe inside the frame, sleeve it in something to stop it rattling against the inside of the tube or it'll drive you nuts!
