Mother in Law Not Coming to Shower

My mom & her 2 best friends are throwing me a shower on the 24th. My husband, his parents, and 1 brother all live over here and the rest of their family lives 1.5 hours away. My SIL is throwing me a shower over there on the 30th. My MIL told me today she's not coming to the one over here because her 3rd cousin's daughter's open house is that day and then she's visiting family after. I was kind of shocked, but at the same time I'm not. Her & my FIL constantly ditch plans they make with us or wait until the day of an event to tell us about it. My mom was under the impression my MIL was coming and was planning something special for all 4 grandparents 😕