Cost might be a factor for something that you could only use at the Manx or Pre TT because of the not inconsiderable noise issues.  I believe the ACU grant a dispensation for those meetings/circuits.  It would not be a simple job to quieten it down for other circuits. A Gilera was brought out for the 50th anniversary of racing at Aintree a few years ago.  The noise meter must have had flat batteries that day.