After proving the engine mapping clampdown had not dented his dominance of qualifying, serial pole sitter Vettel spent time in parc ferme staring at the back of the steering wheels of Red Bull's main opponents in the Valencia parc ferme.
"That's a specific request from someone at that team," predicted former McLaren driver Martin Brundle on Saturday after witnessing the German staring at the McLaren and Ferrari cars before heading up to be interviewed by the world's media.
Predictably, team boss Horner denied the 23-year-old had been ordered to collect information about rival teams' technical setups.
"I think he just wanted to show the world what advertising space was still available on his overalls," the Briton, jokingly referring to Vettel's rear-end that was bent over the Ferrari cockpit for some time, is quoted by German television Sky.
"No. The drivers are all curious and want to know what the other drivers have on their steering wheels and so on. That's typical Sebastian," explained Horner.
"He is always thinking, always wanting to understand something new. An opportunity to have a look at Fernando's steering wheel is not to be missed."