Not only is this show absolutely terrible but they're also stealing music.
http://m.kotaku.com/5979061/coulton-says-fox-wont-apologize-for-ripping-him-off-on-glee

He is looking older, but she definitely looks way younger than she really is. I was shocked when I found out she was older than Dianna, Lea and Naya.

He changed the arrangement, but it doesn't make it his song, since, as I understand, he didn't seek the music's owners for permission to do it. While, yeah, they copied his arrangement, it's all legal.
It's not exactly stealing.
The thing is she is underage and Puck is committing statutory rape, yet it's written as comedically inconsequential.
Sue's basically attempted murder on two seperate occasions and they've played that in the same way. I think that's just how Glee rolls...