Four-time Formula One champion Sebastian Vettel protested the new ban on non-regulatory underwear and body piercings by walking through the paddock with a pair of briefs on over his firesuit ahead of the inaugural Miami Grand Prix practice session.
The FIA on Thursday tightened its ban on non-regulatory underwear and body piercings when new race director Niels Wittich issued a bulletin that makes the rule part of official scrutineering, meaning such choices are subject to review by race officials.
The Aston Martin driver said he thought the FIA was being petty.
"I think it is a bit unnecessary to blow this topic up and probably at this stage is more of a personal thing, I feel a particular way targeted to Lewis (Hamilton)," Vettel said.
"In a way, there's a concern for safety, obviously if you have stuff and the car does catch fire. To some degrees, there is personal freedom and we are old enough to make our own choices."
Earlier, seven-time Formula One champion Hamilton protested the FIA's crackdown on body piercings by showing up at the Miami GP wearing every piece of jewelry he could fit on his body.
Hamilton arrived in the paddock wearing an all-denim outfit with several open buttons on his long-sleeved shirt that showed at least four stacked necklaces. He was later seen wearing at least three watches and with four rings on each hand. He also has earrings and a nose ring.
"I couldn't get any more jewellry on today," he said.
