In SA, it seems to be a matter of individual policy per dealership.
Northside Motorcycles in Fourways, Johannesburg North, have told me they usually accept no more than 200 Km over the stipulated service intervals.
Mine was about 800 miles over by the time they could fit it in to the workshop as they were busy no problems they said just check the oil level and just use the bike while they could fit it in.
To void a warranty claim the problem would have to be due to the bike been not serviced and be directly related anything else they should honor a claim