Legal Matters: Collecting Customer ZIP Codes? 
Beware the Legal Risks

The consequences for violating the statute can be staggering: each violation can result in a penalty of up to $1,000, and a class-action lawsuit can seek such a penalty for each and every instance in which a ZIP code was requested. If a company is found to have violated the law, the only possibility of avoiding penalties is to make a showing "by a preponderance of the evidence that the violation was not intentional and resulted from a bona fide error made not withstanding the defendant's maintenance of procedures reasonably adopted to avoid that error."