Strict case in content URL alias
Even if you don't use pathauto,  Drupal7 can not differentiate case sensitive urls. This 'issue' is not code related,  but it has to be with the database collation. non-binary string comparison are case-insensitive by default.

A solution could be to set the 'alias' columns (menu_router.path, url_alias.alias) to binary (case-sensitive).

Be aware that changing the structure of those two columns in existing sites could result in broken links because paths/alias would have to match base on case.