The move is the result of what race director Alain Adam described as “exaggerated abuse” of the original guidance issued during the pre-event driver briefing.
The drivers were told that track limits would only be enforced at the fast Eau Rouge sequence at the start of the Spa lap because the number of officials in race control for the double-points GT World Challenge Europe round had been reduced as a result of social distancing.
The guidelines resulted in cars utilising the asphalt run-off at key places around the track.
This included the exit of the Bus Stop chicane at the end of the lap, where cars were running across 10 metres of run-off and right up to the tyre barriers.
A bulletin issued on Saturday morning stated that “the track is limited by two white lines” and that “cars must remain in contact with the track”.
The exceptions are the left-hand apex at the top of Eau Rouge (Turn 3), Speaker’s or No Name Corner (Turn 9), Blanchimont (Turn 17) and the exit of the Bus Stop (Turn 19) where the kerbs beyond the white line will count as part of the track.
The bulletin effectively means a return to normal FIA rules on track limits for the Spa enduro and the imposition of penalties for repeated four-wheels off violations.
Three warnings will be allowed per car before a drive-through penalty is awarded.
A driver leaving the track will be allowed the opportunity to “give back the whole of any advantage he gained”, according to the Saturday morning bulletin.
“In the event of a driver gaining an advantage and not giving it back, he [the race director] may award an immediate penalty of five or 10 seconds, to be taken at the next pitstop.”
The warnings will be reset to zero after six, 12 and 18 hours.
GTWCE boss Stephane Ratel said: “Alain said we would only monitor Eau Rouge strictly, so he kind of opened the door and everyone rushed through it.”
Ratel also stressed the difficulties of monitoring track limits during a 24-hour race on a Formula 1 track.
“Circuits like Spa are designed more and more for F1 and this year we have seen the removal of the synthetic grass [laid in strips at some corners],” he explained.
“Monitoring track limits on a circuit design for 20 cars doing a 90-minute race in the daytime is quite different in doing it when you have 56 cars in a 24-hour race.”
The double-points Endurance Cup round of the GTWCE at Spa starts at 3:30pm local on Saturday, and you can watch all the action live on Motorsport.tv.