The Fiance's Parents inviting their friends to the wedding

Ok so we are having the wedding at their house which has 10 acres. We have invite 100 guests. I just found out that the in-laws to be decided to let us know that they are inviting their friends to the wedding. We have been paying for everything and just using their place for the wedding since they offered to let us. Saved us a ton of money by having the wedding there. Long story short should I just bite my tongue and go with the flow. I could understand them inviting people if they were paying for the catering and things. I just fear that I will end up having more guests show up on the day of that I wasn't expecting.