I even have 1 that can remove up to 8 active jamming signals.
Gotta love what you can buy for $20
If China allows those unrestricted chips to be sold internationally but not domestically it would be a strategic long-term decision, I would think. Destabilize the neighbors but not themselves.
The more likely reason is that their government has simply not gotten around to restricting it.
Other than that, GPS is a one-way system, it does not know you exist, how fast your receiver is moving or "give" different information to one client vs another.
Even if it did, this is essentially a toy and moving slower and lower than a general aviation plane.
It uses accelerometers and other sensors because they can be sampled and integrated hundreds of times a second. The $5 gps module is 9600 baud serial and provides one update/second (or maybe 5/sec depending on which part number you pick).