2 Up
On the occasions I have had passengers the beast has not blinked however the progressives did complain to the point of sprouting it's vital bodily fluids.
So from now on I will put the original equipment on when going 2 up which are much better suited to handle that task. Since mine (wife) broke her arm recently she wont get on for a while but no one gets on MY beast without a good helmet. The rest is up to them. 
On the occasions I have had passengers the beast has not blinked however the progressives did complain to the point of sprouting it's vital bodily fluids.