Why it's 'almost impossible' for Spain to police illegal tourist lets

Spanish society and government has spent several years talking about the damaging societal impacts of tourist rental accommodation, so why is it proving so hard to locate and crack down on illegal ones?

Why it's 'almost impossible' for Spain to police illegal tourist lets
Spanish society and government has spent several years talking about the damaging societal impacts of tourist rental accommodation, so why is it proving so hard to locate and crack down on illegal ones?