Old question but I stumbled here so why not take a shot at it since the question is seeking various perspective and not a definitive answer.
w3c may have its recommendations - which I care a lot - but want to rethink since the question is here.
Why does w3c consider domain names be case insensitive and leaves anything afterwards case insensitive ?
I am thinking that the rationale is that the domain part of the URL is hand typed by a user. Everything after being hyper text will be resolved by the machine (browser and server in the back).
Machines can handle case insensitivity better than humans (not the technical kind:)).
But the question is just because the machines CAN handle that should it be done that way ?
I mean what are the benefits of naming and accessing a resource sitting at hereIsTheResource
vs hereistheresource
?
The lateral is very unreadable than the camel case one which is more readable. Readable to Humans (including the technical kind.)
So here are my points:-
Resource Path falls in the somewhere in the middle of programming structure and being close to an end user behind the browser sometimes.
Your URL (excluding the domain name) should be case insensitive if your users are expected to touch it or type it etc. You should develop your application to AVOID having users type the path as much as possible.
Your URL (excluding the domain name) should be case sensitive if your users would never type it by hand.
Conclusion
Path should be case sensitive. My points are weighing towards the case sensitive paths.