We arrived PEK from HND this morning and were refused a 144 hour TWOV. The person at the desk explicitly said they couldn't tell us why. We were one of 7 groups at a set of chairs near the desk that had been refused TWOV, there may have been others we didn't speak to, (given that people don't stay there for hours and most people don't want TWOV this seems like a considerable percentage of people who were expecting to get them). The only thing that seemed universally true is that the individuals had been to Turkey. Two groups had only some members refused and those members had been to Turkey and those accepted hadn't been to Turkey. There was an 8th group, whose member was told, and I quote, that they were rejected because "you travel too much", who hadn't been to Turkey.

I am confident we were compliant with the rules for the 144 hour TWOV, and the check in agent in Tokyo had checked it as well. We actually got a 144 hour TWOV in Shanghai three weeks ago on the same passports etc.

Once you are rejected for a TWOV expect to be pushed pretty soon, and pretty hard, to arrange alternative travel out fast. At least one group were pressured into booking £800+ per person Air China flights back to London. We resisted long enough to find some reasonably priced Cathay flights via HK online (you can't get to a ticket desk and the transfer desk who we were told can help would be flattered by the word useless). Speaking to the Japan Airlines rep who was sent to escort us through to airside for our replacement flight and she said that incidents like this were becoming more common.
I think it's unlikely that we'll get the additional flight and hotel covered by our insurance, even though they are rated pretty well, because they tend to see things like this as transport document issues and not cover them so that's ~£1,000 gone

Our two visits to Turkey were short stopovers in Istanbul for about 5 days combined in early 2015 so neither recent or extended stays.

Personally I'd suggest anyone considering TWOV to weigh up the relative cost of getting a visa against the cost and inconvenience of potentially being rejected (even if they haven't been to Turkey) based on a completely opaque decision with no opportunity to appeal; if they are still interested then I would also check very carefully about expectations around insurance and what your flight options are if your TWOV is rejected.