This question only applies to the College game.
Per previous Q&A answers, all preloads must touch the robot.
Per current practice at World qualifying matches,
it is apparently legal for a stack of tubes to be placed on a robot, with some of the tubes on the stack not touching the robot. Its pretty obvious that a stack of 4 tubes on top of a 17.5" tall robot can’t all be touching the robot.
It would be good to either
A. clarify that this (preloaded tubes supported by other tubes) is allowed,
or B. notify all the referees and the college teams that it is not allowed.
Enforcement of the “not touching the goal post” part of the preload is nearly non-existant as well, but its hard to blame the teams, when it is the refs and assistants that are wobbling the wall and cause the touching. It doesn’t likely affect game play.
Similar issues of “preloads not touching the robot” may come up in any game where multiple preloads are allowed.