I was directing a local ACBL club game yesterday and was called to a table. After 1NT opening, next seat Doubled (Alerted). Double meant one of "Both red suits, both black suits, or a long club suit". Doubler's partner required to bid 2C if third seat passes. It's part of a modified Cappelletti. 2C overcall would have shown a single suiter (not clubs), 2D for majors, 2H for H+C, 2S for S+D and 2NT for minors. The 3rd seat player called me and asked me if the opponents were required to provide a Written Defence. She was convinced they should. I had no idea. In the absence of knowledge I ruled that they did not need to write down a defence. I said they could raise the question to the bridge club management committee but I'm not sure what will happen at that point. Out of my depth on this question and appreciate any guidance - how to deal with this next time, and how to help the management committee decide what to do when they come to ask me about it.