I just wanted to write this out to give people a warning of something that happened to me today in hopes that maybe it can get fixed and/or avoid people this issue.
I was logged into my Xbox One account and was redeeming a 25$ prepaid card, my roommate (who has an account on my xbox and plays live on it under his account name) walked in the room and the kinect picked him up and logged him in as I was redeeming the code. As I hit enter and redeemed the code it credited the money to his account instead of mine, even though I had originally logged in and was sitting in front of my tv with the controller. I'm assuming it's because he walked in and it logged him in last.
Contacted Xbox support and nothing could be done since it's a prepaid, but hopefully this problem can be fixed in the future.