Muni Alarm: Too Loud?

Jameth came across these stickers while riding the L-Taraval. According to him "[t]hese stickers are affixed over all of the speakers of this outbound L-Taraval train. The phone number was scraped off of all the stickers."

A few questions: Should the loud screeeeeeeeeep you hear be silenced? Also, and as much as we're all supposed to hate said loud sound a Muni makes when someone interrupts the door while it's closing, isn't the loud noise the point? To stop people from interrupting a closing Muni? Is there a better onomatopoeia we could've used to describe to alarm?

Oh, and that scratched off number is 415-701-2311.

Image credit: Omega it's jameth