Ferrari has had the right to veto rule changes since the 1980s, although it only became known to outsiders in 2009.
But Brawn, who was technical director of the Maranello outfit from 1997-2006, was unaware of such a thing until very late in his Ferrari career.
Speaking in a new book written by ex-Williams CEO Adam Parr and quoted by F1 blog F1Fanatic, Brawn revealed that he didn't even know about the right to veto when Ferrari were looking to get rid of the 2005 rule change which banned in-race tyre changes.
“I didn’t know that we had a veto then,” Brawn said. “We didn’t use it and I don’t think Jean [Todt, then Ferrari boss] would have ever used it, because we knew it was wrong.”
Brawn also shed some light on Ferrari's decision to race in the infamous 2005 United States Grand Prix.
The race saw just the six Bridgestone-shod cars run, with every Michelin-equipped team retiring both of their cars before the start of the race.
Ferrari were still reeling from the 2005 rule change which meant drivers had to complete qualifying and the race on a single set of tyres, a move thought to have been brought in to disturb Ferrari's dominance.
“We were in a position where we were feeling very aggrieved because of what had gone on with the tyre rules, feeling persecuted,” said Brawn. “So our mindset was not to have much sympathy when the perpetrators of the one-race tyre had a problem.”
Bahrain International Circuit - Winter testing