Sometimes you have a moment of insight and creativity and are really enjoying being impressed with yourself right up to the point when you realize what you’ve stumbled across the stupidest idea ever.

Years ago, I thought won’t it be cool when the day comes that cars have outside screens like the pharmacy uses to remind you it’s flu-shot time or that tuna is on sale.

Setting No. 1 on mine would be: “For the safety of all drivers, passengers and pedestrians, please follow at a safe distance, taking into account the speed of traffic and conditions such as rain, snow and ice. Tailgating is a hazardous behavior.”

Setting No. 2 would be: “I talking to you, Jack. Back off.”

You can see where this goes. It would elevate road rage to new and ugly heights. The roads are already rude and dangerous, and the cops have enough headaches.

Automakers are always offering new features, but I assume this is one on which the lawyers got to the CEO ahead of the marketers. Or perhaps some regulator, in a rare moment of clarity, said, hey folks, don’t even think about it.

So we’re left with the low-tech stuff, the bumper sticker. I seem to recall a Yosemite Sam sticker with a back-off message. The problem is it’s permanent and generic, so the tailgater behind you right now dismisses it as meant for someone else.

Of course, an overwhelming number of bumper stickers are about embracing causes and identity: peace, coexistence, respect, Dodge, Ford, Chevy, seek God, deny God, “I brake for ...,” baby on board, Obama good, Obama not so good, “My other car is a ...” My personal favorite is “Drive defensively. Buy a tank.” Some are affirming. Many are hateful. And many are commercial, another time-honored tradition.

Now comes another development in that same vein. There’s a little buzz this week about a guy – can’t find a name, so there’s a big Internet fake-fake-fake clue right there – who got a tattoo of a KFC Double Down.

For those who might have forgotten, this is the sort of thing that scolds and dieticians call food porn: two breaded chicken fillets around bacon, two kinds of cheese and a “special sauce,” which no doubt counts as a vegetable. I have said no to cheeseburgers too few times in life, but even I am scared of things like this. It’s unhealthfulness wrapped in unhealthfulness.

No matter. The gentleman with the tattoo owns it completely. It’s a conversation starter, he says. And apparently this is, as the kids say, a thing. Others with KFC tattoos walk among us. Somewhere the colonel is smiling weakly, asking for a mint julep and a place to sit as he ponders this extreme form of marketing – permanent, free ad space, and the guy doing the advertising is paying for it.

If we’ll do that with the human body, think of what we’d do with electronic signs on our vehicles. Maybe there’s a reason they don’t let us have that.

I know what you’re thinking: The next logical step is “Extreme Tattooers” on cable, about people who pay to have corporate symbols etched permanently upon their persons. In the world of just-spell-my-brand-right marketing, this is pure gold. As my dad likes to day, they get you coming and going.

Follow Jeff Fox on Twitter @Jeff_Fox.