We received an RSVP card with no names on it and no return address.  I realize now we could have prevented this with an invisible pen, but too late for that now.
I was hoping we would figure it out when we followed up with the guests who did not RSVP.  Unfortunately, that didn't work because some of the non-RSVPers didn't respond when I reached out to them by email.
Any ideas on dealing with this?  We are having assigned seating and escort cards.  I have a feeling it is probably someone from my work, but I am not sure.  I have left a couple seats open at a couple different tables so there will be somewhere for them to sit....the problem is how will they know?
 
Thanks in advance!