My son's soccer team was excellent at the offside trap. But they were also masters of being right next to the defender, listening for the thump of a long ball, and then taking off running. By the time the ball came down, they were 10 to 15 yards down the field, ahead of the defender, and not called for offside, since at the moment the ball was played they were onside.
My first referee class was very enlightening. The instructor, who was English, told us the laws of soccer are written for someone who already understands the game.
Doug in SW IA