FIA race director Charlie Whiting has warned that drivers will not be allowed to gain an advantage by cutting Turn 4 at the top of Eau Rouge at Spa.
A detection device, officially called the 'Cheat Loop' and which triggers when a driver puts all four wheels off the track, has been placed behind the kerbs at Turn 4.
"Any lap completed during qualifying by leaving the track and cutting behind the apex of turn 4, as judged by the detection loop in this location, will be deleted by the stewards," Whiting wrote in a note sent to all teams and drivers.
"On the third occasion of a driver cutting behind the apex during the race he will be shown a black and white flag, any further cutting will then be reported to the stewards.
"Each time any car cuts behind the apex teams will be informed via the official messaging system."
Several drivers were caught out yesterday running wide at Turn 4, prompting Whiting to remind everyone of the rules.