The Great Tape Measure Fiasco in '02 (Zone Zeal). Game was shooting soccer balls in movable goals. You got points for all the balls in a goal on the opposite side of the field from your driver station. You ALSO got points if part of your robot was on the same side of the field as your driver station.
Obviously an incentive to be in two places at once. Teams Q&A’d for ruling on what constituted an entanglement hazard, etc. and it seemed clear that anything long and flimsy was an entanglement hazard and illegal. So some teams went to a lot of trouble making mini-robots or rigid extension devices to reach across the field to score those bonus points.
Week 1 regionals and some few teams show up with motorized tape measures that they shoot across the field. Which seemed obviously illegal. Except the GDC ruled that they were, in fact, legal because they
And thus all the teams that put in a lot of work and engineering to come up with a non-entangling solution were really miffed at a huge rule change after the end of build season.