Exactly this. China also likes shows of strength, and would be more than happy to expend large amounts of cash to bankrupt the people trying this, rather than lose face being broken by them.
If each Chinese citizen were to sell $1000 worth of yuan back to the Chinese government in return for 1000 USD, a trillion-dollar reserve would be depleted.
I don't get this. My mental image is all the toddlers of Beijing queuing at the banks, with a wad of banknotes in one hand and a pacifier in the other, unsure which one to give to the teller.