And Guest?

B and I received a wedding invitation in the mail today addressed to "B____ Lastname and Guest". This invitation came from the son of B's mother's very good friend (someone B has know for years AND we both spent Christmas with last year), so really, what gives? We are engaged. We have been dating for 6+ years. SOMEONE had to call B's mom for our address, they couldn't have asked for my name? I know it had to have been embarrassing that they FORGOT my name after spending hours with me last December, but still, suck it up and ask! There are certainly people out there who I will blank on, but before I send that invitation, I plan to ask someone. Why? Because Emily Post and Martha say so. Am I overreacting? Have you ever received an invitation like this?