Maybe he is listening to music while gaming? Or uploading something completely else. It doesn't matter what he is doing, something like that shouldn't happen.

And it's not just decent/nice to ask user if your app is about to suddenly use 100% of upload speed in the background - it's common sense.

Maybe somebody else in the house is running Spotify? [See "bufferbloat": http://news.ycombinator.com/item?id=2088389]

Well I like to use Spotify for music to listen to while I game..which you know, when I thought the application just streamed I figured wouldnt have much an impact on the game.

Im not saying using p2p in spotify is bad, I just want it to be more obvious and at least a way to control its max upload rate in the program itself. The fact that people need to download a 3rd party app to limit spotify from swamping their internet connection is stupid.

It does actually say in the T&Cs that it's going to use you as a p2p node if I remember rightly, it's been a while since I've seen the header but it was listed as 'Computational resources'.