Someone made a point on the TWOV since 2024 thread that impacts e-channel so I thought I'd bring it up here too.

I believe that itineraries and passenger manifests are reported to Chinese immigration at the point of departure. Chinese immigration then uses this info in a variety of ways, one of which is to approve entry via the e-channel. Case in point: I boarded a flight yesterday using one set of credentials, then tried to enter China via e-channel via another passport (the one registered for e-channel and that has my residence permit). I scanned my passport and was allowed into the fingerprint and facial rec check, but it wouldn't work. One of the workers came and asked me what flight I was on, clicked a few buttons on the other side, and my facial rec and thumb print went through.

This leads me to believe that e-channel checks (at least) 4 pieces of info:

1) Passport and whether you're registered for e-channel
2) Facial rec
3) Thumb print
4) Your arrival flight info

I always knew about 1-3, but 4 also makes sense... the fact that I used a different passport to board a flight meant that this info wasn't transmitted to China immigration ahead of time, and e-channel wouldn't allow me in without confirmation of #4 above.

Another implication is that China immigration can use this information to find out if someone has multiple passports, depending on what information is transmitted to China immigration by the airline.