I believe, the immigration help is mostly for Chinese passport holders that are flying to other countries that may have imposed restrictions causing flight delays and cancellations. Not for Chinese passport holders flying to China other than for those that may experience a delay in their flights.
Apart from Thai airways stopping flying some chinese routes between the 7th and 14th February, unlike other countries, Thailand don't appear to of have stopped flying any routes.
Seems a bit weird all this about cannot go back to China. U-Tapao is busy flying people in and out of China. Chinese are still arriving here other than the tour groups
It's not difficult to see, by looking at the Thai Embassys and consulates worldwide, that the issuing of ME Non Immigrant visas is in It's final days, except for very selective reasons of business etc
Now, I don't know if it's true or not but I can remember something, somewhere being posted, that some land borders won't allow you to clear an overstay and send you to an airport.
They are doing no more than they did for Europeans when the Volcano erupted in Iceland. They simply waive the fines for overstay due to flight delays at the airport. They don't hand out visas on a whim so people can sit on the beach