What do you do when the police come to the house? Ask for a warrant. In this case, the police showed up at someone else's house without a warrant and searched plaintiff. Does she have any rights? Yes.
The case is Payne v. Galie, a summary order decided on September 10. The Fourth Amendment says the police need a warrant to search the house. The Supreme Court has said a non-resident has Fourth Amendment rights "if she is an overnight guest in that home or otherwise enjoys a similar degree of acceptance into the household." But those rights fall away if you are in the house for a business transaction and only remain there for "a matter of hours."
Payne alleges in her complaint that the police "entered her host's apartment without a warrant in order to arrest her." But her complaint does not allege that she had a reasonable expectation of privacy in the apartment. The Court of Appeals (Lynch, Katzmann and Sack) gives her a break. She can replead the case and start again. Normally, the Court does not give people this relief when they did not ask for it in the district court, but plaintiff did not have a lawyer at that time and probably didn't know what she was doing.
Finally, while defendants say that plaintiff has to affirmatively allege that she did not consent to the officers' warrantless entry into the apartment, the Second Circuit notes that plaintiff is not required to plead facts to negate an affirmative defense. That argument will have to await defendants' summary judgment motion, when discovery is complete.