kicking someone off a server simply as your losing should never be allowed... pre game kick sure. IN GAME kicks thou seriously grow some b*ll* and learn to take a loss even if a very high loss Embrosio
of course in duels you do not see your opponent all the time .. otherwise well, they need to learn duel better

it maybe that they warp most of the time, and you just don't see it..
pinpoint rockets, can be spam rockets knowing which entrance to the room is likely, and indeed a skill learned over time, knowing how long it would take a particular person to get to a particular location..
most times in duel meet opponent is for the items coming up or indeed when try to cut off/trap or become the victim of one
so pro spawners know it is actually an offense to kick someone from a server simply because they are winning, this is known as stat padding and if persons report you for it, you will likely receive a warning or indeed possible ban...