I know this isn't directly Chirp related, but it's the right audience, and this information needs to get widely distributed. Nobody in my local ham circles knew about it.
If you don't know what the annoying Yaesu Wires beep is, it's a Yaesu-proprietary internet access feature. It's too easy to accidentally enable on most Yaesu radios, and it injects a DTMF tone at the start of every transmission that masks the start of the audio.
It turns out there's a way to silence the beep, even if you accidentally put the radio in Wires mode. There's a well-done description of the settings changes for a dozen Yaesu models, and an explanation, at http://www.sbara.org/downloads/WIRES/ which has both online html versions and downloadable pdfs.
Hope that helps some, and apologies for the noise to the rest of you.
-dan