I checked in at SFO domestic the other day for an LHR flight, and I was a bit.surprised I was forced to a kiosk, but someone came.over when my light started flashing to help out. Can't recall if she was UA or a contractor.
The first thing she did was tell me I need to check in at the international terminal.
I would have preferred to check in at home but even after scanning and uploading everything I couldn't get a BP.
If they want to alleviate staffing issues, maybe allowing app check-in would be a good starting point.