Accurate, incomplete survey of bus routes

The Israeli OSM community has discussed importing bus routes information from Ministry data. The data contains the sequence of stops for each route but not the sequence of highways the bus would take. However, type=route relation specifies that the ways that make up the route are mandatory members of the relation, and it is not feasible to manually survey the highways information. (It can probably be inferred with reasonable accuracy from the sequence of stops, of course.)

What would be the best way to handle this situation? Would it make sense to import the stops data without highways data? Should we try to infer the highways data (run a routing app on each pair of successive stops, etc)? Or just leave the data unimported?

Personally, I would have thought that adding the type=route relations without member ways would be fine (it would be accurate, incomplete information; requiring complete, accurate information would be making the perfect the enemy of the good), but a counter-argument was presented that the schema should be adhered to.