i can't remember what the stuff's called, but i know that somewhere, i've seen a type of plastic that lets you see through at any angle, and just plain refuses to reflect or refract light.
i've used the stuff at a tech museum (OMSI) where i volunteer, and it's a pain, since the only part of it that you can see are fingerprints on the serface

whenever we use it, we have to wash it in windex so that it doesn't look like there are fingerpeints floating in mid air...
i think it's the same stuff they use in stop-motion movies when they have to make something appear to fly
if FIRST had been able to use that stuff (which is just as strong as lexan) instead, itwould be SOOOOOOOOOOOOOO much easier to controll the bot on the lane you currently can't see... lols...
Z