I am having a hard time coming up with a use case in which case-sensitive min/max parameters make sense and several solid cases for a case-insensitive min/max.
Example:
With case insensitive min/max:
an exact match on /users could be accomplished with min=john&max=john
Currently, for this case, min=john&max=JOHN
seems to work, but it is possible for other values to sneak in there requiring a client side post filter.
Discussed on Finding a user given their (exact) display name and https://stackapps.com/questions/1041 and