There is nothing wrong with placing protectors on any ramps. Best to be safe than sorry.
Gregs offer is remarkabley generous. It will certainly test the strength of the ramps now.
But, i would still use protectors, changing out ramps, depending on the machine could be a real pain in the ass.
Also, why not colour code the standard boring silver protectors to the colours of the pinball machine. A touch of vinyl or paint on any ramp protector set, could make a ramp protector much more attractive !
