The company should try to prevent this from ever happening again, that's for sure, but mistakes, even serious ones, happen everywhere. For example, hospitals mix up babies far too frequently (as mentioned in the article). Further regulation is not what's needed. In my opinion, 23andme remains an awesome service and one that shows we're "living in the future", so to speak.
I find it somewhat silly that on finding out her son didn't match her first though was that he had been switched, rather than that there was an error in the testing. Which is more likely to happen?