... or be put onside by teammates running past them?So when the ruck ends do all the players IN the caterpillar also have to to get back behind the back foot before participating in the game ?
yup. Hence myVERY POOR WORDING.
They seem to have borrowed from the scrum law: 19.29 [...]at least one foot level with or behind the ball.So offside for the player attempting to charge down the kick, but we ignore the blatant offside by the scrum-half moving in front of the hindmost foot to roll the ball back to box-kick. If you want to move the ball, someone bound into the ruck should be moving it.