OK, so, I believe it was risk on pogo.com that has a certain alliance feature. It actually has 2 that I want to bring up. First, there is an alliance button that you can use to send someone and alliance request. This would allow people to REMEMBER that they are in an alliance and other things (this is a shout-out to a certain person who "forgot" about our team >:I). The second feature as a trust rate that shows how often they break an alliance. This would be useful in showing who you can put your trust in. Of course, when someone attacks a teammate the alliance is broken, allowing them to attack back without diminishing their trust rate. There is also a button that allows you to break an alliance. I do not know if they have to accept the alliance break or not, though.
P.S. I was just in another game with that person and they forfeited the game to let me win