Online check in from USA
 

When departing from USA (in my case, from ORD) can I check in online and print my own boarding pass before going to the airport? Or do they insist on a document check at airport before they will give me a boarding pass?

You shouldn't have a problem completing online check in. However, in my experience, being able to get a BP seems to depend more on your destination than your point of departure. For example, I fly USA-NBO-USA a lot and usually don't get a mobile BP on the outbound but do get one on the return which seems odd to me since you think flying to USA would have stricter in person document verification requirements but I think they can validate APIS for the USA via the computer vs to Kenya....I may be way off here but that's my guess.

I'm a USA citizen living in Kenya...I can always check-in when travelling TO the USA, but never get a boarding pass until doc check at the airport. FROM the USA to KENYA, I can always check in on line and get the boarding pass on my phone

That's very interesting. I wonder why our experiences are so opposite? Might be because I use my Kenyan passport traveling to Kenya and my USA one when traveling to the US? Might just be random luck at this point

Could it be that the first segment on any PNR requires a doc check and subsequent segments do not?

When I've done it in the UK with a home printed or mobile pass the passport check has been done in the lounge. They said there that if I hadn't gone to the lounge I would have been tannoyed at the gate to have things checked. Could be different elsewhere of course.

That's my guess. I travel on a US passport. EK to Europe or Asia, I always get checked in and the mobile BPs. But, from NBO to the states, I always have to have a doc check. From the US back to Kenya...no doc check...

Yes doc check alone is not a hindrance to getting a mobile BP, suspect it's a combination of departing airport, destination airport and citizenship.

I've not been called up at the gate but at CPT during boarding as they scan the BP it beeps and they then check passport and destination visa, I sometimes ask them to do the doc check at the lounge proactively but recently they've been saying they can't and it has to be done at the gate. A little annoying as it holds up the line then