Why is Tortoise SVN case sensitive?

Question

I've recently encountered this using TortoiseSVN, but I assume it will be the same for CVS based programs (correct me?).

Out of pure curiosity, is there any reason why the CVS filesystem is case-sensitive? I.e. the following URLS are different:

svn://repo/branches/PROJECT
svn://repo/branches/project

Is there some legacy reason for this? It gets more intriguing on a file basis. If 2 files exist in a directory, lets say ProjectOne.vbp and projectone.vbp, one will overwrite the other in a normal Windows filesystem (or, as I have encountered, throw a cryptic TortoiseSVN database error), but can co-exist peacefully in the repository.

Now obviously it's up to the user to not use ridiculous naming such as the above, but are there any advantages that I'm missing to having case-sensitivity?