That higher standard sounds similar to "Double reasonableness" from British tax law.

"Double reasonableness" is used to delete tax advantages for certain things which you say were correctly exempt from taxation or attracted significant tax advantages but the government alleges you were in fact just generally avoiding paying tax and whatever you were doing doesn't count. It's not a crime to have mistakenly believed you didn't owe tax, but, if a court finds against you, you would now owe the back tax, plus potentially penalties.

The "double" comes from a requirement that not only can the reasonable person (say, a juror) not think of any way that what you're doing isn't just avoiding tax, but they can't even imagine any other reasonable person who thinks what you were doing made sense for another reason beside avoiding taxes either.

The idea is this only triggers for people who are very obviously dodging tax, so that their scheme sounds completely ludicrous unless it is explained that they hoped to avoid taxation, rather than just being a slightly eccentric thing to do which happened to have tax benefits when they did it.

"I buy and sell used cars" makes you a used car dealer. No reason you shouldn't take advantage of used car tax treatments which are a significant benefit.

"I let somebody else do all the buying and selling" OK, I guess you just own the business? Nothing wrong with that, small business, entrepreneurship, excellent.

"I don't own the business or anything, I just get the advantageous tax treatment". Huh, well it's very good of the people actually doing the transactions to let you benefit while they go without, very generous indeed, but at least you're ensuring a healthy market in used cars.

"Oh, there's just one car. That car is just bought and sold over and over again to make up the amount of money I requested". See, now that's ludicrous, why would anybody believe you had some reason to do this except to avoid paying taxes?