As a foot soldier we all know the proper way is to kill the horse first then have everyone swarm the rider, who will actually get more points from proximity team wounding than the guys trying to kill him. If, by accident, the enemy range kills the rider first, us friendly infantry will kill the horse; hopefully seconds before a dismounted cav on our team runs up to it.
The order of ranged targets is 1) Cavalry 2) 2-handers/polearms 3) shielders 4) ranged 5) mounted ranged. This is chosen by a combination of most dangerous/easiest to hit/most annoying to all other players. The only thing ranged wants to do is get rid of everyone who could interfere with their favourite game of pew pew. Pew pew takes a lot of patience and concentration, and that is hard to do when someone could sneak up behind you, so its only when all melee cav and infantry are gone that they can finally relax and try hitting each other from the far sides of the map.
