from my understanding of criminal law there is more than just that, a dwelling will have a greater expectation of privacy than a vehicle or a person in public in many states. Exigent circumstances, like immediate dangers to others, destruction of evidence (sometime),fresh pursuit into the dwelling can allow police to enter without a warrant or consent, but the general rule will apply that the P.C. can get you the warrant, but you'll need that to enter. Also the issue of possible consent will be a factor as well, who can consent to a search in a hotel room, the owner, the manager, another guest. The fourth amendment is the bread of butter of a lot of criminal defense attorneys.