Hi, I'm checking in on this thread as I too would like this feature. Is it something planned for MMA 2.0?

Peke wrote: ↑Sat Jul 02, 2016 9:15 pm It is already on out to do list.

It is already on out to do list.

Often when I'm listening to a song on my phone, I will decide to add it to a playlist. Easy enough, done. But when I get hom and sync, I realize that the track was already in that playlist, and there's now a duplicate.

Could we get a warning, as we do on MMW, that the playlist already contains an entry for that track?