Ahead of this weekend's Australian Grand Prix, as revealed by Motorsport.com, F1 race director Niels Wittich has reminded the teams that their staff scaling pitwall fences is outlawed under the FIA's International Sporting Code requirements and is subject to penalties.
This constitutes a new clampdown on a long-standing tradition of F1 team members climbing up and leaning through pitwall fences to cheer home their cars achieving notable results.
This is because, though it was already forbidden in the FIA's rules, it was not previously policed, until scenes of Red Bull and Aston Martin mechanics climbing high on the Jeddah pitwall fence last time out (as they also did in the Bahrain season opener) led to the governing body opting to act.
It is understood to fear grave consequences should a person or object fall onto the track, or if a car sent debris towards the areas of concern.
When asked for his reaction to the move by Motorsport.com in the team principals' press conference in Melbourne, Horner said: "I was surprised it was an issue, to be honest with you.
"I think anything that it relates to safety, obviously one has to take very seriously. But, it's a fairly iconic moment when you see a grand prix car finishing a grand prix and its team celebrating one a fence.
"And, so long as it's done in a manner that is safe, I, personally, have never seen an issue with it.
"I've [always] thought it's been a part of grand prix racing and we've achieved that 94 times as Red Bull Racing and not once have we had an injury or looked like there being an issue.
"But, if they're the rules, they're the rules."
Sitting alongside, Horner, McLaren boss Zak Brown said he was "not exactly sure what sparked the necessity to change it," and that he was "not aware of an incident".
But he added: "That being said, safety is critically important to all of us and if they feel it's potentially not safe, then those are the rules and we'll all stick to them."
Aston team principal Mike Krack confirmed his drivers Fernando Alonso or Lance "will certainly not pay the fine if the team jumps on the fences", with the stewards understood would be told to consider such monetary punishments should the new clampdown require action at a future race, rather than impose a sporting penalty on a driver.
"I think it's something that we need to respect if it's a pure safety directive," Krack continued. "And, if that is the rule, then we will comply with it and if someone doesn't [at Aston] they will pay the fine.
"Here, it will be quite difficult to climb fences because it's just glass [lining the Albert Park pit straight to increase visibility for spectators.
"So, one [possible problem moment] saved."
