[ipv6-wg] Hijacking unused address space for a private infrastructure - any legal consequences?

Hi all,
Could somebody speak on the legal consequences of hijacking unused address space?
Imagine the situation that some vendor would push many Carriers to use FC/8 by cutting a rather big block out of it (/28 for each Carrier).
This address space should have a registry. It is an IANA property till then.
But:
1. Nobody is using it - nobody would be hurt.
2. This prefix would be excluded from the Internet (by routing and filtering)
3. FC/8 is assumed to be used for the closed domain (the purpose of usage is very similar). Just nobody decided how exactly. Maybe /28 is not how IANA and IETF would want to split it in the future.

People could ask "why not GUA"? The answer is: it is difficult to get yet another /28 GUA from RIR just for the infrastructure.
/28 goal has the technical roots by itself. It is the sort of technical solution.

Could such LIR/Carrier have any pressure from any RIR or IANA itself?
Is any restriction in the LIR agreement?
Any legal consequences? (that would push for renumbering).

Of course, I am aware what may happen if Carrier would need to connect infrastructure with different Carrier or Cloud Provider
Without proper random prefix generation and registry to guarantee uniqueness.
The technical side is very clear for me. I am just very ignorant on the legal side.

Disclaimer: This question is not related to Huawei, not at all.
Eduard