I'll admit I'm not up to date on the permissions and capabilities of the latest Blackberry or iOS version (if they're up to spec, then this app is by all means for them, too), but on Android smartphones, there are apps available (free apps) which allow you to modify their behavior by texting a certain code to your smartphone. Behaviors that can be modified thusly include, but are not limited to, locking the screen, enabling the GPS chip, wiping all data from it, and overriding silent mode to increase the volume to max power and sound an alarm. The expected purpose of such apps is, of course, to help locate a lost/stolen phone, prevent its data from being accessed by anyone who finds it that isn't you, and destroying all data in the event that you've given up hope on ever finding it.
I have a different purpose in mind.
My idea is for an app (hopefully available cross-platform, but if iPhones must get left out because the designers don't want to play ball... well, that's a sacrifice I'm willing to make) which partners with movie theaters. When you buy tickets, you provide your phone number and, if you haven't already done so, download the app. At the time the movie is scheduled to start, or maybe 5-10 mins prior, a text is sent to your phone to activate the GPS, if it's not already activated. If it detects your phone is more than, say, 1/4 mile from the theater you are scheduled to be at, it triggers a loud chirp to get your attention, and displays an on-screen message reminding you about your movie appointment. If it detects that you are within 1/4 mile of the theater, it automatically silences the phone for you. At the time the movie ends, your phone receives another text code to re-enable the ringer so you don't forget.-- 21 Quest, Dec 19 2012 Great idea! You could have it be associated with Fandango or something so that you could use the same app to order the tickets. That way, no text would be required, just access to the clock and GPS.
I would humbly suggest that it go silent at the theater rather than at 1/4 mile though.
Also, one downer is that, at least for Android, I have been told that apps can not turn on your GPS- that has to be done manually. With a lot of people, and me, it wouldn't matter, since I leave it on all the time anyway. On my old phone, GPS was a big battery guzzler, so I always had it off.
I think they were concerned that baddies would miss-use GPS to locate victims.-- Kansan101, Dec 19 2012 I'll have to check to see if that was disabled on Android 4.2. It worked on earlier versions.-- 21 Quest, Dec 19 2012 I think it was disabled on 1.8, but there was a work-around that worked until 2.2.-- Kansan101, Dec 19 2012 Most phones in the States went straight from 1.5 or 1.6 to 2.1 or 2.2. But I guess you could always root/jailbreak if you have a compatibility issue =)-- 21 Quest, Dec 19 2012 I have heard that rooting an android really increases the functionality a lot, that everyone should do it. Unfortunately, I don't own my phone. It's employer owned.-- Kansan101, Dec 19 2012 random, halfbakery