This is the way it was handled over the weekend at Spa for the 1000 km:
Friday (I wasn't there): only after the second practice, the CotC decided to go for "4 wheel over" reporting, but only if the driver gained some time. Shortly afterwards it was changed to "report all" and big penalties were given.
Saturday (me at Blanchimont): we had to report every car over the kerbs, for whatever reason. For practice the penalty was as follows: for a first time the fastest time was disallowed, the second time the 3 fastest laps were taken away, third time the driver ended up at the back of the grid. During the races penalties were only given if the driver gained a place. No reporting had to be done for the rest that went over.
However the French Porsche Cup overdid it a bit and all of the sudden after the race, they were asking for numbers that went over the line. As a lot of the Observers in Belgium are not the smartest, they tend not to write anything down when not needed, so Race Control did not get much out of their late decision to revert back to penalties.
Sunday: haven't got a clue what they decided next.