As mentioned, Texas is a state where they routinely check.. Auction sites, and on side of the road.. Had one friend of mine get checked on side of the road, which i witnessed myself.. I had another friend who like myself owns a construction company, claim they showed up at his office location one day checking trucks for red fuel.. Most often around here they will travel with state troopers, and in some case i have heard troopers themselves do it... The trend seems to be stronger when fuel prices get high, and people seek relief from the prices by burning the red stuff.. I know many who have done it with zero issue's , and generally after a couple of full tanks are cycled through a truck, all traces are gone.. The friend who i know who was road side checked was proof of that.. He was really sweating bullets that day! Folks its tempting, and i will say if i were in a situation i had no choice[side of the road/boon docks] i would do it in a heart beat, but only as a last resort.. One last comment, i will add.. I have bought a few trucks from the state of Arkansas, all with red fuel in the tank... I guess they are exempt, or there is some paper work involved at the end of the year for using it..