Our dairy cows have activity tracking (heat detection/poor health detection) collars, and they work fine with lockups. The cows do turn their head a bit differently to make sure the collar clears, but they learn quickly and we've had no deaths yet (200ish cows, 5ish years of using the collars)

Yes getting in and out of a stanchion is a scary experience for the cow and human both! Adding a chunk around the neck that could make entering and exiting more difficult can pose risks for both parties.