RICHMOND, Va. — Fan overboard.

It thankfully didn’t get that bad Saturday night at Richmond International Raceway, where the indelible image from the most lackluster race of the Sprint Cup season was a half-naked man brazenly swinging his arms while sitting atop the turn 4 catchfence as traffic whizzed below.

But if he had fallen, please know the entity with the most at stake in such a nightmare scenario tacitly supported such absurdly dangerous behavior via its Twitter feed.

When the race was yellow-flagged as the unidentified fan was coaxed down to be detained and charged with disorderly conduct and being drunk in public, the @RIRInsider account tweeted, “Hey fence guy… +1 for most creative #RIRselfie. #nascar”

Yes, it’s all fun and games until someone plummets about 20 feet and gets slammed by a 3,400-pound stock car at 130 mph.

Then it’s game over — for NASCAR, RIR and quite probably the public reputation of auto racing.

It isn’t uncommon for fans to rush the field of play during a major-league sporting event. But for obvious reasons, it can’t happen — nor should it be glorified or saluted via a flippant tweet — during any form of auto racing.

A sport whose competitors already flirt with death every time their engine is toggled can’t afford to ask its spectators to bear the same burden, and NASCAR has had too many recent reminders of those risks.

A Nationwide Series crash at Daytona International Speedway in February 2013 injured more than two dozen in the grandstands, and a loose TV camera rope hurt 10 at the Coca-Cola 600 a few months later. Both prompted disconcerting talk of congressional oversight and crushing liability claims.

What separates the Richmond incident is a fan somehow was allowed to put himself in harm’s way.

Spokeswoman Aimee Turner said the track would “review safety measures with Henrico (County) police and NASCAR.” That implies there was some lingering mystery as to how a guy barely in command of his faculties managed to scramble to the top of a barrier in plain sight of an allegedly attentive and adequately staffed security detail.

Reviewing the oblivious reaction of security in the video and photos of the climber, the natural conclusion is systemic incompetence at a track that now must evaluate whether it invests as much energy in protecting its fans as promoting them.

And it happened against the backdrop of a sport that has bent over backward incessantly catering to its supporters over the past five years, creating a permissive environment in which fan access has skyrocketed as its popularity has dwindled.

In April, Richmond held a “track takeover,” in which anyone with a ticket was invited on the track before the green flag. After Saturday night’s race, everyone in attendance was allowed on the track for a party celebrating the Chase for the Sprint Cup field (some driver PR reps grumbled that security was lax for a crowd containing many as inebriated as the fence-climber).

Having severely limited entry to the garage 10 years ago at its zenith, NASCAR tracks now hand out hot passes like candy.

It smacks of desperation that breeds a pervasive sense of entitlement among those buying tickets. Fans rarely are told no, and they continually are reminded their voices are helping dictate policy-making, whether it’s the advent of double-file restarts, earlier starting times or revamping the Chase for the Sprint Cup format.

Everything seemingly is done, the NASCAR industry constantly stresses, because fans want it. Governance seems mostly by vox populi essentially in the interest of vanity — elevating fans to the center of attention as much as the stars whom they’re supposed to be cheering.

The emphasis is on making the world safe for selfies, a major focus of RIR’s social media campaigns. In one of many Twitter photos of the man atop the fence, he appeared to be snapping photos of himself with a smartphone.

As always with NASCAR nowadays, a fan was calling the shots.

Follow Ryan on Twitter @nateryan