Blake wrote:
> b := a msg.
> b msg1.
> b msg2.
>
>     Do I misunderstand? (And at what point does the potential for 
> confusion and ambiguity outweigh the feature?)
>
Yes.

The message sent to a is #asPipe, not msg:

p := a asPipe.
p msg.
p msg1.
p msg2

Or alternatively:

a asPipe
    msg;
    msg1;
    msg2

The Pipe arranges for each message to be sent to the right object.