Towing a manual yaris

[tooter]

I was wondering about that, too.

The only cause I can come up with is that during towing, any parts of the transmission connected to the flywheel are not in motion. These transmission parts are everything that's on the engine side of the neutral disconnect, which may include some gear clusters. Running the engine before driving spins these formerly inert parts insuring that they are properly bathed in oil before becoming engaged to the load of moving the vehicle.