[Arragonis]

I vote for balance too. I doubt they would worry that much about wind noise on their entry model car, but a heavy sensor is going to make it a PITB for tyre fitters and be more of a problem for most owners.

Having tapped that I would also expect a dab of paint or something similar to indicate the best position of the wheel on the hub for balance.

Back in the good old days of British Leyland Mk2 (aka Austin-Rover) they used to balance the wheel on the hub and then mark the best position.

EDIT : Entry level - FIT of course, but the same issue applies - balance is more likely to be an issue.