Do they need to know where they are at every given moment, and collect data on each customer in association with where they're coming from and where they're going?

No, they just need to know where they are when:

1. They run a collection routine 2. The bike/scooter is low on battery.

There is no info they need in association with the rider's trip. Or at least not, as the GP states, info required "by nature". That perspective is true of ride sharing (the driver needs to know where to pick up and drop off) but false in relation to bikes/scooters (no need to know start/end points, just need to know where the bike is during collection or low battery, and not in association with a rider).

The rider uses an app to find a bike/scooter near them. That requires real-time location data

And also to be rented, if the user doesn't happen to have one in sight.

They need to know where the scooters are but they don't really need to know where the customers are though.

Consider a similar system that would work with coin operated scooters. They can have GPS in the vehicle without constant association with users.

In any cases these two tracking databases, where is each scooter and who is on which scooter, should be separate so they can provide the former to law enforcement without disclosing citizens whereabouts.