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.

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.