So I see why FOB devices are great and useful to maximize profit for bars with long draw systems. That being said, when a keg of Beer A kicks, the FOB prevents the foam from flowing through the line and then you want to put Beer B on that line next wouldn't you just end up with a flow of first Beer A and then Beer B right after that? Like wouldn't they kind of mix together? Obviously if you're putting on a keg of the same beer it makes total sense but I am just confused at how this would work when you're putting on a different beer next. I am studying for my Cicerone exam and just want to be clear on this one. If someone could clarify that would be great, thanks!