URLs are case sensitive. Coding around such a fundamental reality will probably be damaging in the long run.
IIRC this is not *completely* true? (but its been a while since I was reading the appropriate RFC's etc...).
Some sections of a URL are case-insensitive. E.g. the DNS system is case-insensitive, and IIRC web-server developers are requested to make their filenames case-insensitive BUT "case preserving" - e.g. so that URL queries that contain data e.g. from a form are not transformed?
Ditto IIRC the protocol field in a URL/URI?
I remember a time when many webservers were case sensitive, but that has definitely changed - but this could easily just be for convenience so I really don't know.
P.S. Case sensitivity is, in general, a bad idea in user interfaces. OTOH it is just as powerfully a very very good idea in non-user stuff, like code; not because it makes it easier to write code, but because it's easier to transfer around data, where different case has a lot more meaning, and case-sensitive systems can safely be used as a vector for such data (e.g. linux cannot [always], as described above, and this is a pain and a problem). IMHO, URL's are aimed more at users and so ought to be case insensitive; ditto filenames. I use both sensitive and insensitive FS's so much I automatically know which is which without thinking about it, but IME it has often been the cause of many problems and bugs in multi-person teams...