This ruling does not explicitly outlaw double climbing. This update only clarifies what was already known for this season that teams could not give each other fully functioning mechanisms for climbing such as what was done in 2017.
Teams like 2630 Thunderbolts have developed a buddy climb using forks that deploy under the robot which does not violate this rule since the robot being lifted is unmodified.
Other teams like 1678 and 3360’s buddy climbs do require modifying the robot being assisted using a piece of Velcro or a hook respectively but these minor alterations being considered major mechanisms is debatable.
Considering that the hook or Velcro on the assisted robot do not accomplish the end game task on their own and require a second robot, I’m of the opinion that they do not violate this rule but I’m not an inspector.
Speaking more to Hyperion directly I believe they said that if their hooks were deemed to be in violation they would pass out instructions for teams to build their own and get around the rule that way. I’d assume 1678 would do something similar by handing out free Velcro.