Out of medication, US woman boards flight from Peru to US

[marble falls]

3. Why should Peru care about Equador entering Peru, the Equedorians don't care ...

reciprocal agreement require enforcement by both sides as in: Peru won't let compromised Peruvian originating traffic enter the US and in return the US won't let its compromise traffic leave for Peru.

There's bureaucracy and paper work on both sides and a mechanism for allowing certain cases through. This is just one problem with running ports of entry/exit in the time of the Trump Pandemic.