Someone please confiscate his shift key. Return it when he has learned to use it responsibly! heh heh
Pascal casing is too arbitrary for my taste; WebMasterWorld or WebmasterWorld is a perfect example. But I think as long as your pages have only one canonical spelling (regardless of case), then you can use redirection to sculpt your file path into PascalCase, camelCase, lowercase, UPPERCASE, StuDlycAps, or whatever you want. I stick to all-lower case for everything, and I believe I'm a happier person as a result.
If you have different content at PageOne.html and pageOne.html, well then you're just asking for trouble, aren't cha.
W3C's URI pages are a cute example using a 300 status header, though the average person will see the title of that page and think "300 choices? I only see 3 here. Where are the other 297?". Status 300 is a disambiguation page... No wikis (a logical place to use a 300 header) I've ever dealt with use them properly, AFAIK the W3C is the only site on the entire www that has ever employed a 300.
I'd have preferred a Permanent 301 to the canonical URI.