The guest list has been finalized and the invitations have already gone out. We have 250 people to hear from. My FH's mother has invited an additional 3 people that were not on the list. FMIL did not ask my parents, the hosts of the wedding, if she could invite these additional people. At at least $100 a plate, these extra guests add up and we are worried that she is going to keep inviting people. We want to keep the number of attendees as low as possible because of the significant cost. I asked FH to tell FMIL that we were happy to invite the additional guests (even though she wasn't asking us) but that we would like to be asked first in the future. Now groom's parents are very angry and feel that they shouldn't have to ask us to invite more people. The groom's parents haven't contributed a dime and apparently they just do not believe FH that a plate could cost more than $10. Any advice or commiseration?