So I'll pull this thread back because I unexpectedly had the chance to use them as an AR last night in a boys varsity match. The center had the motorcycle-style comms system, open mic. I REALLY enjoyed using them. I had two comeback offside calls in the first half where I was able to call it through the comms as my flag was going up. No delayed call from the center at all. There were also a few times where I was about ready to flag a foul, but the center called "No" over the comms. It saved me a wave-down. We were also able to identify a case where a player was beginning to tread near the PI line as well as both ARs at separate times mentioning that some players were starting to come in hard after the ball was away. The tape I was using came undone in the final 20 minutes or so, but that was the only real logistical issue. The fans also got a kick out of the fact we were using them. The first time I called a ball inbounds ("in, in, in"), someone noticed my headset and said, "Look, the referees are using walkie-talkies!" A couple of times, I mentioned that the center's call was good, and I think people overheard me and didn't say much since a second referee also agreed with the foul call. I'll definitely look at getting my own soon. It was fun.
Best recommendation I've ever gotten: clear medical tape, put it on before warming up. If you can't, then wipe off any sweat from your face before applying the tape.
Lot's of clear medical tape. I work with a lot of guys who just want to use a bit of clear tape because of the look but it always ends up falling off.
For those who use or might use comms, PRO's week in review talks about AR-R teamwork on fouls, and is largely about communication through the com systems https://www.proassistantreferees.com/mls-week-in-review/week-11-may-8-12