I wouldn't go that far. According to a reputable source, Car tires and trailer hitches are noted on the workorder anytime dealer service is performed. That work order becomes part of the bikes history and is tracked in Triumph's computer system. It might not void the warranty but it could be used for a warranty determination somewhere down the road.
The Maugneson Act prohibits any OEM from denying warranty claims because of aftermarket add on or employed acessories (in this country) but that don't mean the OEM can't pro-rate any repair.