When I first joined several years back we had an issue like this pop up around one of my bows...because I backed it in kevlar. Of course it's not primitive, but at the time I was mostly just wanting to find a group of people to share my new hobby with. Not to mention, that's all I had for a suitable backing. I had a lot of people, including the mods and admins here, complain because the kevlar was modern and, thus, was not to be discussed on this forum. These were all the same people who preached the use of band saws, hand planers, titebond III, etc.
Here's my beef with the situation: I could care less about performance. To me, performance is in the lumber, not the snot holding it together. My .2 mil layer of kevlar barely held the grain down. I don't have an issue with anyone using modern materials...modern materials are awesome, and you can not tell me for a second that the bowyers of centuries gone would still be using cat gut and fish spit had Titebond III been there. To me, it's all about the lumber, and the people who claim that glass and Loctite and such are "sinful", per say, should start posting up their bows made with zero modern influence (not saying some of them haven't...I just haven't seen, nor searched, for them).
I love this forum and I love seeing the things people come up with, but I have a hard time looking at this as a competition, and, thus, find such rules a little hipocritical. That's my opinion, though, not that anyone in particular asked for it.