Probably not every find, but in cases like this where you are looking up the resource based on the params, I'd tack it on.  Also, throwing it on `find` won't work as `find` already raises the exception if a record is not found. Dynamic finders like `find_by_user_name` will return `nil` if the record isn't found unless you tack the `!` on the end.  I hope that makes sense