Drilling a hole wasn't my proposed solution. My proposal was to simply string an Ethernet cable between the two balconies. It's cheap, fast, very effective, and ugly. It's temporary, though, so the ugly part can perhaps be forgiven.
Someone else suggested drilling a hole, and then a follow-up suggested that they'd have to buy a drill, etc. My comment was simply, don't most people already have a drill? The answer, apparently, is no. I've always had drills, I have five currently, but I guess not everyone is like me.