With respect to priority routing--does everyone understand priority routing?
Priority routing starts with the financial institution that issues the debit card. If a financial institution chooses to offer two competing networks on the same debit card, the financial institution can either predetermine which network is processed first at the point of sale or they can allow the cardholder to choose the option they prefer. So when a financial institution predetermines that option, that's priority routing. If a merchant, for example, accepts all of the networks that are on that card, the terminal will automatically preselect the predetermined option and process the transaction in that way.