Yes and the only way they can do this on a large scale is if they coordinate with all banks in the region, which all get the trust of the populace. This can happen in a government, but even then people can take their tokens out onchain if they suspect foul play, so long as the government wishes to maintain the illusion of transparency. These people can then flee the country or set up a thriving parallel market.

For this to happen between governments would require a federal government (cartel) to coordinate (like the EU). The larger it gets, the harder it is to stop crucial economic actors from exiting the system. This outflow will eventually give way to a collapse of the local ecash economy and increased popular interest in real BTC or alternative ecash issuers outside of the regime. Like how Argentina had a thriving black market for dollars when the official exchange rate was distorted.