My fiancée and I are planning a wedding for approximately 150-160 guests. We're currently at 152 accepted. With 27 days left to go, my fiancée's auntie calls him saying that 16-20 uninvited guests are planning on attending the ceremony ONLY. The ceremony is at our local church which can hold more than 1,000 people. Then we have our reception later in the evening. According to my fiancée, they are extended family members that he hasn't seen in 3 years. They are coming from Northern California and Las Vegas. They only found out because his aunt was asking her sister in that extended family and they obviously didn't know about the wedding because they didn't receive an invitation.
What would you guys do in this situation? Would you let them just witness the ceremony? Or say no. Only those with an RSVP are allowed to go?