Also, if someone like "round" number, they can also choose 15 instead of 11 as scope for the "narrow" routes. It would work too:
However, they have to make sure that no other unintended routes with scope=11, scope=12, scope=13, scope=14 (real scope values as seen in the Nexthops table) also have dst-address matching the gateway, otherwise those routes might be picked when the scope=15 route is down.
It's safer to keep target-scope as low as possible to reduce the pool of potential candidate routes.