This is correct and refers to the Monza type filler caps. A "R" clip must be fitted around the hook of the spring catch to prevent accidental opening during racing. This does not involve drilling the catch as the "R" clip rests against the body of the filler cap thus preventing the catch from moving. At the fuel stop, pull out the "R" clip and put it back again after refuelling.

This new regulation will be included in the final instructions

Regards Jeff Kirby (MGP Chief Scrutineer)