Imagine your employer accessing your company-issued phone to see whether you attended a union meeting.
Or, how about your spouse checking it to see whether you're visiting an old flame. Maybe a probation officer wants to check it to make sure you're not associating with some criminal buddies from the past.
Or maybe, just maybe, the FBI wants to check with Apple to get a list of everyone who attended an antiwar protest that got out of hand.
These are the kinds of privacy concerns raised by revelations last week that Apple iPhones keep detailed, easily accessible records of where a user has been. A free Mac application called iPhone Tracker will take your iPhone's location data and map it for you using Google maps.
Rest assured that attorneys and prosecutors have seen the news reports and that subpoenaed iPhones will be a common occurrence within weeks.
GPS chips, which cost just a dollar or two for manufacturers to include in a phone or a camera, are proving far more costly to our privacy.
The precision of the information is troublesome. EXIF data, embedded in the photos you shoot with your GPS-enabled phone or camera, can provide ne'er-do-wells with the location of a photo within a couple of feet.
That photo of your children in their bedroom that you posted to a Web scrapbook? If it contains GPS data, a criminal can tell not only where your house is, but which bedroom of the house the photo was taken in.
That $1,000 barbecue in the poolside photo you posted? Thieves now know where it is in your backyard.
Laws and court rulings haven't kept up with the explosion in the availability of data and gadget manufacturers have assumed that pretty much anything goes.
Apple isn't alone in this. Google uses Android smartphones to do some scary things as well. GPS data from your Android phone is sent to Google every few minutes, and that data is used to do everything from updating freeway traffic maps to locating virtually every Wi-Fi router in the world by its unique identification number.
Although Google assigns each phone signal a unique identification number, the company claims the number is not traceable to specific handsets. On the other hand, there are no laws preventing it from doing that in the future.
Both Apple and Google say it's up to users to protect their privacy. They say if you are concerned you can switch off location tracking on your phone and avoid location-tracking apps.
The difficulty with this is that there are many good features to GPS, and more and more apps are location enabled. Getting driving directions on Google Maps isn't easy without GPS. Your camera app, as mentioned earlier, uses GPS. Yelp, Facebook, FourSquare, AroundMe, literally thousands of apps use GPS; it's part of what makes your smartphone so useful.
Want to use your banking app to find an ATM? You need GPS. Want to find a restaurant nearby? You need GPS.
Turning off GPS on your smartphone makes it a lot less smart.
What's needed is the ability to set the precision level of the data you share. It would be a lot less threatening if you only recorded data with an accuracy level of a mile, for instance. That should be something technically easy for developers to implement, but don't look for it soon unless they're forced to do so.
In the meantime, here's what you can and should do about protecting your privacy:
1. Be aware that you are a walking or driving blip on someone's map. Do you really want to use the "Check In" feature on Facebook that maps where you are? A few courts have already ruled that the data can be subpoenaed.
2. If you have an iPhone, go into the "Location Services" setting and review which apps you really want to have access your GPS data. If you're going somewhere and you don't want someone to know, you also can turn off all location services.
3. If you post photos to the Web, be sure and strip the embedded EXIF data first. Some websites will automatically do this when you upload a photo, but not all. Google's free Picasa photo album program will show you what data is embedded in a photo if you need to check. Photo editing software, if it has a "Save to Web" setting, typically will strip the data out.
4. Untrackerd, an app for jailbroken iPhones, allows you to erase the location data they keep.
We all should be pressuring phone manufacturers and legislators to impose limits on the use of GPS data. Just because something becomes technically feasible, that doesn't mean it should be done. Hopefully, at some point legislation will catch up with the technology. In the meantime, you've been warned.