I use Kytephone on my mobile to manage the apps my daughter can load when she's playing games on my phone.
It replaces the launcher and requires a password to disable but connects to their servers to authenticate. Twice in a month their servers have been down, this time has been all day, and I've been locked out of my phone. Luckily I installed another launcher through the play store on the computer which deactivated it.
And even though I was back running my usual launcher it was blocking my calls until I uninstalled it. Just realised, though, that they sent me a code win an email when I registered to unlock it when there's no net access.
Yeah, if you turn off WiFi/data the password you use won't work. There is an unlock code which they send when you register or you can get off their website (not if it's down like today).
"We're introducing this change so that we can show a powerful application full of high-quality content, rather than what we have now which is a equal mixture of awesome and sadness"