It may not be a full fledged cliche yet, but I've seen it more than a couple times lately: The unattended smart phone.
Our hero or heroine (or a friend of theirs) leaves his/her smartphone out where anybody can get to it. Then the bad guy, usually a backstabbing co-worker sees it and either doctors some pictures and puts them out on the web, or sends an incriminating e-mail that looks like it was sent by our hero.
So, next time you leave your smartphone around for anybody to see, make sure you delete those pictures of you coming out of the love hotel first.
Edit: While re-watching "Tentai Kanzoku" I discovered this cliche goes back to at least 2002. Manami Konishi picks up Odagiri Joe's phone, starts to read the message, then stops. Hadn't realized it had been around this long.