Apple’s App Store rules are designed to maintain a level playing ground for developers and keep them from overtaking the operating system’s interface or feature set in ways Apple did not intend. But at times, the rules also bump up against innovative leaps in terms of how we could use our smartphones.

Case in point: a walkie talkie-like messaging app called Punch has come up with a way to let users message their friends directly from the iOS lockscreen.

Unfortunately, it does so by talking over iOS’s lockscreen music controls – something that will likely keep the beta version of the app with this feature from being approved by Apple for release into the iTunes App Store. (The current version of Punch, now live on iTunes, does not have the lockscreen functionality.)

That said, it’s certainly a clever trick.

The idea for the app comes from Rio de Janeiro-based founder Alessandro Berio, who had previously developed a social networking app Thinkr, which reached a few hundred thousand downloads before he shifted his focus to Punch.

Work on this walkie-talkie style messenger started around a year-and-a-half ago – and was inspired by a desire to deal with the growing texting-while-driving problem. In fact, it was a personal experience that sparked the initial concept for Punch, Berio says: his mom was in a car accident caused by a teenager who was texting on her phone.

What makes Punch more interesting than your typical chat app – at least in the beta build that will probably never go live – is the way it uses the lockscreen’s music controls to support messaging.

“One day, as I was driving back from a road trip, I put a song on my iPhone that was hooked up to my car, and the album cover was displayed on my dashboard,” says Berio, when explaining how he came up with the idea to use the lockscreen.

“That’s when I thought it could be possible to use Album Covers to show photos that people send you and use the music controls to choose to whom you want to talk. By doing this, every Bluetooth car system could immediately become a walkie-talkie and your Apple headphones could be used to walkie-talkie by clicking the mic button.”

Punch’s lockscreen controls work by taking over the lock screen music player. You hit “Play” to record an audio message, and hit it again to send. Where you would normally see the album cover art, photo and video messages appear.

The app also offers a “drive mode” that reads your texts to you, animates the photos you send in a similar fashion to Live Photos, and makes funny push notification sounds when you send emojis. Plus, Punch users can both receive and hear walkie-talkie audio messages even when the app is not running, as it uses Apple’s newer VoIP Push technology.

The beta version of Punch doesn’t use any private APIs, but it seems to violate the spirit of Apple’s rules if not their actual declarations. One does not simply take over a feature like the iPhone’s lockscreen Music Controls and turn them into the front-end for a mobile messaging app.

In other words, consider Punch as an interesting – and working – concept of how lockscreen messaging could work if Apple ever wanted to go in that direction.

Thankfully, Berio has not put all his eggs into this one basket. In addition to Thinkr, which is now in the process of being sold to a media company, there’s still the simplified version of Punch, and Punch’s three-person developer team is working on a third app.

The startup also has a little bit of angel funding (over 1 million Brazilian Reais) to keep them going, and are in the process of negotiating a seed round from an institutional investor in Brazil, he says.

Asked what the plan is when Apple (inevitably) rejects the full version of Punch with its lockscreen access, Berio replied that the team will keep innovating and won’t be discouraged. And they’re willing to take the concept to Android instead.

“We’re not looking to break any rules per se, we just think this lockscreen experience we created is inevitable and necessary,” he explains. “We may also look at other platforms to develop further our project, however we still feel passionate about developing on iOS.”

Pressed further, Berio confirmed an Android app is already in development, and could launch in a few months or sooner.

Early adopters should note that Punch doesn’t work on the latest developer beta build of iOS, but you can see a live demo of the app in action in the video below.