that's like harley riders with unmuffled motors "for safety".
On the other hand, I remember being in japan and watching some construction vehicles in tokyo. They were surprisingly quiet. After a while I realized what it was - in the united states all construction vehicles have these annoying "beep-beep-beep" sounds while they're working (for safety).
I wonder if one day they can play those only when someone walks nearby or play in some technologically quieter way.