1997 Law 40E1 said:
The sponsoring organisation may prescribe a convention card on which partners are to list their conventions and other agreements, and may establish regulations for its use, including a requirement that both members of a partnership employ the same system (such a regulation must not restrict style and judgement, only method).
2007 Law 40B2A part said:
As I see it, the only effective difference is the default: if there is no regulation, then players may play different methods under 1997, and may not under 2007. Agreed?
EBU Orange book 10A2 said:
The EBU's regulation, unchanged with the change of Law books, does not permit different methods.
Please can someone tell me what the WBF said on the matter for their competitions, say in 2006 and 2009.