Mine's a 5S running 7.0.2 on Verizon. I have Touch ID and a long passcode. This screen shows up once in a while if you:
1. Click the Wake/Sleep button to look at your lock screen
2. Click once on the Home button, but don't leave you finger on it to unlock
I'm not too bothered. iOS 7 in general seems a little unfinished so I'll chalk this up to just another instance of lack of polish. At this point, 6 years in, with the team on a tight schedule every year to ship by a certain date, and with all kinds of features (that weren't originally anticipated) tacked on, the underlying codebase is probably looking a little bloated. When you're under the gun you probably don't take the time to carefully refactor all the interfaces/classes/methods. Plus there are so many more devices to regression test for. On top of that there's the whole retargeting to 64-bit.