This is not true in all circumstances. Banks will not provide loans to those who have defaulted, and this is true for both private loans and those subsidized by the government. And contrary to what you state, and especially in the present economy, banks are not as willing to throw money our way simply because we are going to be doctors. This is particularly true for those who already have an considerable amount of debt, as they are more likely to default.
Honestly, I think the question about outstanding debt has far too many people worrying unnecessarily. I highly doubt interview invites are based on this. Regardless, it's a question that everyone will have to address, whether it's on the secondary or after you have gained acceptance.