I really wish they'd hurry up and make this a requirement. Everyone uses a headset anyway, even the crusty b00mer types who make $300k but can't be bothered to spend any money on a decent headset.

The only seriously unsafe things I've dealt with at UAL were exactly for this reason. Crusty dudes refusing to use intercom, either can't hear me or can't hear ATC, whatever. It's a huge safety issue, and I'm sure the subject of many an FSAP. The sooner they put this into SOP, the better. There is zero reason to not use the technology, especially when communicating is the single most important thing we do in CRM.