A short sale may not absolve the debt owed. It is strictly on a case by case basis. In reality, how are lenders going to enforce paying what is owed by people that are bankrupt by most accounting standards, unemployed, or have little assets.
There are thousands and thousands of people who entered into a short sale or walked away and for many it is apparently a socially accepted thing; right or wrong, it may be difficult to curb in the future unless there are strict guidelines in place to stop it from happening again.