We got nailed with a BSA audit, and we dutifully complied. We counted up all our licences, did a full systems audit, etc, and found we were out by 1 licence, which we purchased and listed as such on the audit. Note that the audit requires you to do a complete licence count back to Windows 95 and such- things that are 15+ years old.
The BSA's response? "We don't like some of your keys, so trot out all purchase records back to 1998." This was two years ago. We keep financial records for 7 years, as required by law, so we did not have receipts back that far. According to the BSA, we are therefore out of compliance, and have to repurchase the software.
We said to them, "we're done with this, this audit has cost our company thousands of dollars in effort, and will no longer comply with your requests." Haven't heard back from 'em since.