A recent appeals court ruling allows police to gather data from a cell phone without getting a warrant. The case in question had police finding three cell phones during a drug arrest, turning them on, and recording the phone numbers so that call records for those numbers could be obtained. The judge seems to draw a fuzzy line between getting this kind of information and searching for calling, browsing, and email information without a warrant. There's some point where the police would go too far, but he doesn't seem to make that point very clear.
If you're carrying a cell phone, especially a smart phone, then you are carrying around a device that holds a highly concentrated dose of your private information. Who you email, text or call, what pages you surf to, and any searches on the GPS are all there for anyone to see who can get to it. And if this decision is affirmed by higher courts, it means that the police can take basic information from your phone, use that to find other information, then possibly use that information to get a warrant in order to go further into the phone.
I'd be interested to see what putting a hard-to-guess passcode on your phone would do. My iPhone doesn't give its phone number unless its unlocked, and of course you can't get to the higher functions of the phone while it's locked. Recent court rulings hold that a defendant can be compelled to decrypt a hard drive, so I'm guessing that a defendant could be compelled to unlock a phone or face additional charges of contempt.
In the same vein, using any application that would wipe a phone remotely could be construed as destroying evidence, dragging whoever runs it into your trouble even deeper than they may already be. All the authorities have to do is compel your cell provider or phone vendor to show records of access to your account.
And remember, the authorities are much less likely to get hold of your phone than Sumdood is. Getting your contacts, personal information, passwords, and banking information would certainly make his day. Safeguarding your data against him and his ilk is at least as important as keeping it safe from Officer RoidRage.
So what can we do?
The only thing I can think of is to lock your phone and get a lawyer. I'm sure there are a lot more things you can do, and a lot of shades of gray in all of these. To be honest, I still believe that a majority of police aren't out to mess with the populace in general, but there's always that one guy. Taking a few steps before there's a problem can mean that you control when the information on your phone becomes available to the police, and you can do it under advice of counsel.