There are many unwritten rules Simon, A chielf Marshall has to use common sence and experience.
Such as this could be considered unsporting, least I think that's the term we used recently at the Agm. Not In the spirit of the sport?
Eg, there is nothing to say you cant wear a fishing belt thing with a cup and put your drop down hamster in it on a stander. but its unsporting as it will or could be perceieved to give an advantage.
As a chief marshall, I would not allow either (and many others!)
I appreciate Suds may be struggling, but so have others and hence after many false starts, we arrived at the Open class. Problem solved.