Adding a route in subnet-up and subnet-down breaks the idea behind Tinc of creating one large Tinc subnet and using smaller local networks. For example, Tinc network 10.10.0.0/16 and local networks 10.10.1.0/24, 10.10.2.0/24, etc.
By setting the route, it becomes impossible to route traffic into the other networks. Therefore, the option to set the route should be made disableable.