You CAN Refuse Warrantless Searches
"Warning: If a police officer asks your permission to search, you are under no obligation to consent. The only reason he’s asking you is because he doesn’t have enough evidence to search without your consent. If you consent to a search request you give up one of the most important constitutional rights you have—your Fourth Amendment protection against unreasonable searches and seizures.
A majority of avoidable police searches occur because citizens naively waive their Fourth Amendment rights by consenting to warrantless searches. As a general rule, if a person consents to a warrantless search, the search automatically becomes reasonable and therefore legal. Consequently, whatever an officer finds during such a search can be used to convict the person.
Don’t expect a police officer to tell you about your right not to consent. Police officers are not required by law to inform you of your rights before asking you to consent to a search. In addition, police officers are trained to use their authority to get people to consent to a search, and most people are predisposed to comply with any request a police officer makes. For example, the average motorist stopped by a police officer who asks them, 'Would you mind if I search your vehicle, please?' will probably consent to the officer’s search without realizing that they have every right to deny the officer’s request.
If, for any reason you don’t want the officer digging through your belongings, you should refuse to consent by saying something like, 'Officer, I know you want to do your job, but I do not consent to any searches of my private property.' If the officer still proceeds to search you and find illegal contraband, your attorney can argue that the contraband was discovered through an illegal search and hence should be thrown out of court."