Mil asked us where we were staying on the weekend of our wedding, me and dp are staying together the night before as aren't doing things the traditional way. Planned to get ready together and stroll down the he registry office and meet family there.
I assumed that she asked because she didn't want to book the same place, it was the opposite she wants to stay with us at the same hotel so she and her dh can get ready with us and have breakfast etc together.
She knew our plans, we told her but she's booked the same hotel thus going against our plans entirely.
Hotel is non refundable.
Not much I can do now but aibu to be a bit miffed.