Looking at the current rules we have.
12.2 Bike changes are permitted for mechanical reasons only. Any bike changes must
therefore take place on the off-road sections of the course.
and also
15.1 No cyclists or support riders (except competitors) have permission to go on the
following sections of the course:
1.Gill Garth – Ingelborough
2.Brunscar (Chapel-le-Dale)-Whernside-Blea Moor
3.Up and down Pen-y-Ghent from from the gate half way up.
Commissaires to enforce this regulation. Any competitor in the race connected with a
cyclist caught breaking this rule will either be penalised or disqualified.
So gaming the system with balsa wood bikes is a non starter.
I’ve ridden the event 5 times now and helped out, either marshalling or supporting club riders quite a few times as well. When you have a team of people supporting multiple riders it quite easy to do it in a considerate way. Last time I helped we had 5 or 6 riders and put support in after Ingleborough, before and after Wherneside and at Phenygent so we didn’t have people trying to keep ahead of their rider by dashing between locations. For individuals being supported by a single other person this is harder – especially as your sharing some sections of the route with the riders.
It used to be that marshalling the event guaranteed you an entry for the following year, if you wanted it, but I don’t know if that is still the case.