I see that you understand that the user can step over all of your existing routes by creating the corresponding username.
, ( ):
$route['(:any)'] = 'users/profile/$1';
$route['my_trigger/(:any)'] = '$1';
* , /(:any) .
, my_trigger , .
, , , "", . , /blog /trigger/blog.
, , url, /u/username, , ?u=username.
- , , , .
, - , "" (.. ).