What would you rule?

[iviehoff]

The opponents are entitled to know what you know about your explicit agreements and implicit understandings. What you plan to do with this knowledge is irrelevant, they may want to take it into account in their bidding or defense.

Agreed, but there is a difference between entitlement to know (if you ask - which you won't), and an alert to draw it explicitly to your attention. That is why I asked if the fact of partner being likely to forget the meaning of a bid was a factor that would suffice to make it alertable, (presumably the plain meaning not being alertable).

[barmar]

Whether something is alertable depends on the alert regulations of the jurisdiction. If the regulations don't address this specifically, I think the default would be that if the "forget" meaning, or the implicit 2-way meaning from his tendency to forget, is alertable, I think you need to alert it.

 

Under the old EBU regulations, where you weren't even allowed to mention partner's tendency to forget, it obviously wouldn't have been alertable ("Alert!", "Please explain", "Sorry, I'm not allowed to").