A nation must think before it acts.
Recently commercial vessels in the Black Sea reported incidents that have led analysts to manifest concern about Russian efforts to spoof GPs systems in the Black Sea and beyond. While there is no definitive proof that these were Russian activities; we do know that Moscow has both talked about and experimented with technologies and capabilities that would allow it to spoof GPs systems. While the potential for military threats against naval ships in a time of warfare in the Black Sea and elsewhere is obvious; we should also take into account the possibilities for the use of such a weapon as an instrument of commercial or economic warfare up to an including piracy in both the Black Sea and even in the Caspian Sea. And if this capability eventually spreads others besides Russia may be able to get hold of it and use it for their own nefarious purposes.
However, for now we need to focus on what Russia could do with this capability and not only against NATO or other military challengers in the Black Sea or elsewhere.