[logn]

Take the email address and search on Facebook, LinkedIn, various blogs, etc. At the least you could be re-assured if the person looks like an upstanding citizen. And if you reach out on a trusted social network, the person might actually respond. It might also send a "I know who you are" type of message. But don't be too persistent, you're probably just freaking the person out. And if you upset this person, well they have your info.

Also, go ahead and get set up with an identity theft monitoring service. You'll know the instant a new credit line or address change is made.

Like others have said, the vast majority of people have no interest in identity theft. You realize that as a manager I have access to hundreds of applicant's passports, driver's licenses, etc.? You know how many people see your social when you apply for a mortgage? Ever considered how many average restaurant servers could steal your credit card number?

Anecdotally, I sold my car to a dealership which years later I realized had my social security card and birth certificate in an obscure compartment in the car. Probably the worst documents to lose. Nothing came of it.