That only works in a limited scope. If a country didn't report any cases and another country discovers it and finds people coming over with it they will trace

That only works in a limited scope. If a country didn't report any cases and another country discovers it and finds people coming over with it they will trace it back. The country loses trust and gets labelled as untrustworthy. That's kinda what happened with China. They covered up / downplayed and played with rules around defining whether a test counts. The WHO helped surpress this. Now the WHO has lost respect (and financing). China has lost face.