Interesting. Did she add that such deals need not be explicit, that what we call altruism is just fulfilment of a trade we make by accepting the risk of sometime needing help? If one posits that, absent charity, there would be more theft and violence, one can see the promise of altruism as a trade for greater safety. We needn't agree with the premise to accept the logic, i.e., virtually any act of apparent selflessness can be styled a "trade" and thus consistent with Objectivist ethics.