Am I insane or just my company?

I was recently put in charge of abolishing spam for our company. After analyzing what was already in place, I noticed that we were allowing alternate names( ex. JSmithay@company.com instead of JSmith@company.com) to be trapped in one of our filters so that a technician could sift through them just in case a legitimate email was caught in there. My question is: Should we be held responsible for a customer mispelling an employee email address?