IME TAP in Lisbon apply the requirements more strictly than immigration officers.

There appears to be confusion with regard to visa waiver and visa on arrival; for visa on arrival the regular visa requirements still apply and those include proof of hotel reservation, return ticket, invitation letter etc. TAP ask for all of these before letting pax on the flight, even if chances are that immigration at MPM doesnt ask for all these documents.

Visa waivers apply only up SE African countries plus some other Portuguese speaking countries such as Brazil and Cabo Verde.