No, they can't. They need a warrant for your cell phone. In fact, there's been some cases that have come out from the Supreme Court recently that have said just that, that cell phones are subject to the same privacy requirements as your home, your car, anything that's in your possession, and there's developing case law on this that cell phones are being given the highest priority as far as privacy because of all the personal information that's kept on cell phones. They cannot search, they cannot look at your cell phone, search your cell phone, without a warrant.
