Yes fair enough, before I wrote that post I thought that I was able to check her into a hotel airside but I see that's not the case.

We've changed the plans slightly...but not sure if this is viable. She will spend a few days in Shanghai and then come to the airport just before my flight arrives. I have a 5hr 40min layover, is there a decent chance the airport officials will let me go out under the 24 hr TWOV if I either explain to them that I have a friend waiting in departures or I could say I want to get a few hours sleep at the transit hotel in the airport landside?

I am flying China Eastern all the way, so wondering if it's possible / safer to ask them not to check my bags in all the way, so that I'm "forced" to go through security and immigration and recheck in at Shanghai to ensure I can meet my friend?