+10x small world nowadays.. especially with the advent of the worlzwidezwebz. Things like this have a way of coming back and biting you in the a$$. This is completely wrong. No one is coming to look for you for giving a good reference to a bad employee. Companies don't contact the reference again after the fact. Once you give the reference, you no longer have any involvement or responsibility at all. Not to mention the fact that quite often an employee is great at one company/job, but unfortunately is doing poorly at his new job. A reference isn't a guarantee - all you are you saying is while this dude worked for me, he did a great job. End of story. Nobody is promising that he will also do a great job for you, since he did for me. References are overrated anyway. People don't give bad references now, because the employee could sue you. The laws have changed in this regard. All you can really do is give a great reference or simply acknowledge that the employee worked for you.