[bayindirh]

> e.g. the distinction between file.txt (lowercase L) and fiIe.txt (uppercase i)...

Just want to remind a little but extremely important thing: There's absolutely no guarantees that upper("i") is I. There's at least one language breaks that convention, and you won't believe how a big headache is that.

[hvdijk]

Good point, Turkish uppercases i to İ. This adds complexity to the idea of case insensitive file systems even when only considering ASCII.