RB tbh you have had a good thing, UMG recognised and respect you using their music in the video, they just want to stake a claim to it as there's which is their right, the advertising they are talking about could simply be a "Buy this track" which results in monies to that company. Always make sure to put the appropriate copyrights in your video and/or description, this usually keeps them off your back.
Iced: It is definitely the GTA IV vids, I had a notice for firstly Uncle Vlad which I actually asked people to Flag and explicitly warned of "Graphic Violence", then they removed "Final Interview...", the one with the lawyer and then finally for some strange reason they removed "Five Star Pursuit", where after a failed attempt at the Bank Job I grab an ambulance and escape a 5* wanted level, that one has me perplexed why they would want that one removed. I can understand the others seeing as they're missions but that one just seemed weird to me.