A while ago my HTC phone started showing full screen ads whenever I unlocked the phone. It was a bundled app called Peel Remote which changed its behaviour during an update.

I took some detective work to figure out which app was causing the issue since there's no visible clue on the ad itself, and since I have never used Peel Remote. I eventually figured it out somehow and disabled the app. I imagine that lots of other HTC users are still dealing with this.

HTC should really protect their users from this abusive behaviour by their partners.

EDIT: Mention that I've never even used Peel Remote, which makes the ads even more annoying!