If you wanted to make sure this didn't happen again, the PAUSE indexer could be patched to do case-folded comparisons so that module authors would be warned of this kind of conflict.

Yes, I'm unsure exactly what to do about this. While I could see warning future module authors about it, the problem is that there are already modules whose names differ already in case. You couldn't easily prevent uploads of modules whose names case-insensitively conflict with other modules unless you wanted to prevent all of the authors of the modules that already exist from uploading new versions. It would probably be too heavy-handed to make a bunch of people change their modules' names.

I guess you could prevent people from uploading modules whose names have never been used before but conflict with others case-insensitively, though. Still, maybe just warning authors is the best solution.