The police are allowed to search your phone, your papers, your home, anything, once they go to a judge, present their case, and receive authorization. The person whose property is being searched has no voice in this case, and in fact isn't even necessarily aware it is being made until they are presented with the warrant. It's literally the most trivial of checks and balances, provided you actually do have a need to search that single individual's property. The goal of these warrantless search rules is to allow dragnet searches of EVERYONE's property.
Think of a warrant as similar to those "hash cash" anti-spam concepts: It's really easy to do if you have a single email that you want to send, but if you're looking to send 100k indiscriminate spam messages, it's going to slow you down.