I am not sure what you are trying to do with your examples. Can you explain the intent?
Set was just an example object that's quick to test the behaviour. My intent is to understand this behaviour, bc. Smalltalk usually goes to great length to keep the messaging system consistent. But in VisualWorks the behaviour is the same, so I presume (and Marcel confirms) that without this the performance of the whole system suffers.
greetings, Lorenz