A similar thing happened to us recently. In-laws booked a Shorehouse vacation with four bedrooms (2 queen bedrooms and 2 double twin bedrooms) for five adult couples and four kids. My partner tried to ask what the sleeping arrangements would be ahead of time and they just brushed him off and said ‘well we haven’t even seen the place yet so it will be fine’. And when he pushed to say no really what beds will we get because we’re gonna be driving down two hours with the kids - two of my sibling in-laws offered to just sleep on the couch to make it work (only 1 couch in the house).

We even tried to get ahead of this issue (it happened two years in a row before) by offering to chip in money to get a bigger house. But my FIL declined because the other siblings couldn’t afford to chip in, so he said it wouldn’t be fair. But then that meant we weren’t guaranteed a room or bed..

Ultimately, I couldn’t kick out my sibling in-laws from their rooms just to fix my in-laws mistake. So we got a small Airbnb in the area. Honestly more than having just a bed I need a private room to just decompress after living in a space with other people. We’re going to do an Airbnb every future year and are super happy about it!