As it is said rules are made to be broken. In the most patriarchal societies there are aways a subset of women who are feisty. Recently a friend of mine who was in BsAs narrated being shouted upon and scolded by a local man who was her friend, when she cabaceo or asked him. They were going to milongas together. For a long time I have been telling her to ask men when she is not getting asked. The BsAs experience scarred her. I told her whoever that man was, he was being idiot for the way he reacted.Whilst I have no personal knowledge, there was this comment on the Codigos thread. People we know who travel frequently to BsAs indicate that it is, of course, done, but wasn't the custom. But I'd just take it as another 'myth' from the history of AT and social customs in a particular locale.
Personally I don’t give too much credence to it being BsAs custom. In other partner dances too, a man is suppose and expected to do the asking. Therefore I wonder how can it be hyped up as some unique BsAs custom. I view it as no different than norms and mores which said woman have to cook and men have to earn, that were almost universal across different societies till 20th century. I haven’t read any codiga that says woman shall not ask. If two people like dancing with each other, cabaceo is very helpful and discreet to facilitate asking and no one will no codiga is been broken