Would be using more than the allotted amount of non shattering plastic used as a decoration be against the rules?
You’ll have to convince the inspectors that it is non-functional. This includes using the material in any way that could interact with a game element, unless backed up with legal material.
Well when I say it’s decoration it’s just a sheet on the back of the robot to hold stickers and the name of the robot.
Here’s what the inspector (and the rules) will question: does the presence of the sheet of plastic on the back give a functional capability? For example, without the sheet, could a stack of cubes fall into your robot (thus it is a functional guard), or does the sheet ever touch a field perimeter (thus it could be part of an alignment system during autonomous. If the sheet is backed up by structure (1x5x1 c-channel or 5x25 plate) then its fine.
Cool, it’s not going to serve any purpose other than showing our name and a few memes from past years, but we will take that into consideration!