Most states have laws that cover permissible reasons for landlords to enter tenants' homes in the absence of the tenants' permission. They may do so when there's a true emergency, such as a fire or gas leak, and when it's clear that the rental has been abandoned. But a request by a police officer to enter a rented home, without more, is no justification for the landlord to turn over the keys. The same is true for hotel operators. Of course, if the police return with a warrant, that's another matter--just as the tenant cannot refuse entry, nor can the landlord.