Stats suggest that whilst learning relay systems and highly compex bidding systems play goes out the window. From personal experience and watching other players, I would suggest that this is true. However, once learnt, the benefits are interesting. I play relay for the other features of the system, but I bet,(without reading stats on hand shapes) my defence has also improved substantially. Systems designed to confound opponents disappear rather quickly. Systems designed to facilitate optimum contracts and also optimum defence persist. Please allow experimentation, whilst protecting cross grade events. Any *good* player should be able to cope. Let bridge progress from being a "protected" baby to being an aggressive teenager, or if we are that aged, a responsible adult. At top level events, we should all be able to defend any system. Allow BSC without written defences. Grow up