[blml] Obviously this is the prime duty [SEC=UNOFFICIAL]

[David Burn]

[KC]

If alerting a bid partner doesn't expect you to alert is not "communicating
through alerts" than what is?

[DALB]

Alerting a bid that partner does expect me to alert is, by this token, also
communicating through alerts - "it's all right, partner - I've remembered
the system". Do you suggest that this is illegal?

[KC]

If are giving your opponents an explanation that you know is going to wake
up partner that you are breaking L73B1.

[DALB]

There are (at least) two ways in which we may prevent communication from A
to B. Either:

[1] we prevent A from saying anything; or
[2] we prevent B from hearing what A says.

Now, since A is required to say something when asked for an explanation of
his methods, we cannot follow [1]. Therefore we must if possible follow [2].
That is one of the reasons why we use screens in certain competitions, and
why we prevent alerts and explanations from being seen by partner in online
bridge.

In most cases, however, we cannot physically prevent B from hearing what A
says - screens are not used in bridge clubs, and it is impractical because
of time considerations and general convenience to send B away from the table
every time A gives an explanation. Therefore we construct a legal framework
in which B has a duty not to act on an awareness of what A says, since the
effect of this is the same as if B had not heard it.

If, therefore, I give an explanation to an opponent, I do not "know that it
is going to wake up partner", for I know that partner will act as if he had
not been woken up. If he fails to do so, of course, he is in breach of the
Laws, but I do not know in advance that partner is going to break the Laws.

[KC]

If 

a) your partner is unaware of the system mishap
b) you say something at the table - something you can be 100% certain he
will hear (this is why an analogy with the waiter is false)
c) your partner becomes aware that you're having a bidding misunderstanding

then you have just communicated to partner that the wheels have come off.

[DALB]

So what? Since partner will not act as though the wheels have come off, the
effect is the same as if I had not communicated anything to him at all.

David Burn
London, England