I've only heard of this, never seen it happen. I have yet to see off road diesel. REC gas, yes, but that's priced between midgrade and premium. It's also what is typically used for most generators and small gas powered equipment as ethenol tends to make them run less efficient. I could care less to try and sneak off road diesel in my truck. I run mostly wmo anyway, but adding regular gas to it thins it and the truck runs like it has diesel in it anyways. I wouldn't doubt it though if some IRS agents wanted to investigate, I'm sure they would want to tax any wmo or wvo for road use and slap a fine on whoever for tax evasion. I just find it hard to believe how taxed we are on everything. The dollar is taxed just to earn it and taxes just to spend it. The government wants to make sure people are paying their fair share in taxes, hence the huge bill the tax payers have to pay for all these extra IRS agents. My only question is,will this speed up my refund after I file taxes? I doubt it...