The AMA BOM memo made prefabs and ARCs virtually legit. Allowing ARFs is almost a formality. Most ARFs need to be stripped of their covering anyway, in order to make it through a competition season. Orestes went with the new interpretation of BOM. Working from prefab composite pieces. Then again, with composites, what other choice is there. Unless the builder of the model makes up the molds and does the casting. No problem with Orestes' current approach given the wholesale reinterpretation of BOM. In the past, I thought buying sheeted foam wings pushed the envelope of BOM, since a straight wing, ready to paint, is the most difficult stunt plane component to get right. A moot point now. But overlooked when the pre-sheeted foam wing could have been an issue. Peabody is of course right. Some members of our hobby raise the old guards' hackles. Other folks do not. As far as the AMA reinterpretation of BOM, no one has ever explained the origin of the memo. Sure the AMA did it. But who in the stunt community discussed it with AMA officialdom, instigating the clarification. It's possible the current interpretation of BOM is based on the precedent set within the RC community where pre-builts fly in pattern events. Also, no doubt, the current proliferation of ARFs and ARCs required a new look at BOM.
Personally, I wish the BOM was more stringently enforced. Requiring the modeler to actually build 51% of an aircraft. The designs developed in the past were works of beauty and effectiveness. It's doubtful that we will see the equivalent burst of creative energy today. Impossible for many reasons. The gutting of the BOM rule is one factor, among many others, that separated the builder of the model from the flier of the model. Reducing the insentive for a flier to be original and build well.
On the plus side (and this is a big plus). ARCs, ARFs, prefabs etc. allow many to compete in stunt, who would not do it otherwise. Probably it would be beneficial for us to bend with the times. Keeping things as they are or eliminating BOM all together. Our hobby/sport would be more likely to survive.