M-. rings bell if empty

[jidanni]

Type "# RET ESC ."
Bash replies with a ^G
Wouldn't it be more polite to just do nothing, instead of waking up the 
neighbors?

$ expr 2 + 2
4
$ #e=mcHammer <-here I typed ESC #
$ e=mc        <-here I type ESC . ESC . in order to get the "2", but
after the first ESC . I must endure the ^G slap in the face, before
being allowed to climb back up to get the 2. There I was playing secret
agent man with the formula and you had to ring/flash, alerting the N.
Korean border guards.