The FIA could find a scientific basis for reviewing the track marks.
The FIA hasn’t found irregularities and no other team has protested Red Bull over alleged Traction Control. The FIA has more cameras than us, more info than us, F1 teams have spies on the track and in the pitlane, I think in today’s F1, it would be really hard for a fan to find something on the car, someone from inside the paddock could not.
Sometimes when you see the lead the RB builds over the first couple of corners as it did at Montreal, it’s hard for anyone to accept that the car does that simply on aerodynamic superiority but then again maybe it does.
Vettel is a pretty good driver, his set up might have been better than the Mercedes’, the Mercedes’ were different strategies, Webber and Alonso were already behind due to having to break earlier with cars in front, Webber even cited his car was overheating due to running so close to the guy in front of him. Vettel doesn’t grab such a lead simply because of aerodynamics, but because of a lot of factors.
As the saying goes “where there is smoke there is fire” so I think there’s a good chance that Red Bull are not entirely playing by the same rules but I would imagine they are using a loose interpretation of the FIA rules versus blatantly breaking them which would at least give them some fighting ground and the chance to contain the damage to the team and brand should they be caught.
People claimed Ferrari had illegal traction control prior to its legalization in 2002. Proof was never found. People were also sure Kimi was going to Williams in 2012. At some point in 1998, people were sure Schumacher was going to join Hakkinen at McLaren, which people were sure of were also cheating somehow that season. The saying is nice, but like in real life, doesn’t always mean the full rumor is true.