[gnasher]

 mycroft, on 2014-December-01, 14:06, said:

It's a question we've discussed before: is "partner has UI, which limits his actions to unsuggested LAs, and he's picked this one. Am I allowed to use the fact that I've given him this UI and what limitations he would have in my further bidding?"

Isn't it also a question that we've answered before, by reading Law 16A1?

A player may use information in the auction or play if:
a. it derives from the legal calls and plays of the current board (including illegal calls and plays that are accepted) and is unaffected by unauthorized information from another source
[b-d snipped because they don't apply]

The knowledge that partner was constrained by UI is, obviously, affected by the UI. Hence you may not use this knowledge.

I believe that North is bound only by 16A3, not by 16B. That is, he may not base an action on the information, but he's not required to "not choose from among logical alternatives ..."

[blackshoe]

 mycroft, on 2014-December-01, 14:06, said:

All the I - that I passed UI, what the LAs would likely be, the fact that partner is ethical enough that the call he made isn't going to be flagged - is, I believe, Authorized. But allowing this seems - wrong.

That last is why, I think, people want to rule against it. But I don't think the laws support that.