Some Chinese employers of foreign teachers,, many of whom are in the public education sector, will only offer air fare reimbursements in part or in full to FT's who have purchased either a one-way ticket or round-trip tickets, economy-class, for travel back to their homelands.
Tidy sums of money are there to be had for FT's who have no intention of leaving China in the short term, or indeed forever. Such FT's could theoretically purchase air tickets in order to receive reimbursements at the conclusion of their contracts from their employers, and subsequently cancel their air tickets to recoup what they had paid for them in full or in part. I'm led to believe it's possible to purchase insurance which includes penalty waivers, but maybe not for most airlines who operate flights out of China. As far as I know, the cancellation penalties vary from 10% to 20%, according to the ticket price and, the carrier if sufficient notice of cancellation is given and the ticket is not a super-saver.
By the way, ticket refunds by Chinese employers of FT's tend to vary between 3,000 yuan and 10,000 yuan if reimbursement in full is not part of the contract.
As I've never been a frequent flier, I'm not well-versed in these matters. I wonder if anybody has anything pertinent to add.