The situation you're describing would happen if there's no transition period whatsoever. If the plan is to stop using pesos overnight, that would certainly be c

The situation you're describing would happen if there's no transition period whatsoever. If the plan is to stop using pesos overnight, that would certainly be catastrophic. You can avoid that if you say "we'll stop using pesos by X date. Until then anyone can trade their pesos for dollars at any bank for a fixed exchange rate of Y pesos per dollar. Businesses will be required to accept dollars by Z date, and can reject pesos by W date."