Need advice for a WW who left

[dwh15]

dwh...

why did you say this?

Me: (hour later) Hey. Kids were asking about tonight. Did you have plans?
Me: So are they set for dinner?

I explained why in the post. We have an informal arrangement where she takes the kids every Mon, Wed, and Fri. Seeing as how it's a Fri and I had not heard a word, I wanted to confirm if she was planning to spend time with the kids or not. If not, I needed to make arrangements for dinner for all of us. Over the past few weeks, WW has been unreliable so even though we have this arrangement, it's never 100% safe for me to assume she will follow through. She has cancelled on more than one occasion, and often with little notice. I don't see any problem with asking about the kids on a night she normally takes them. Am I missing something? If so, please let me know. I'm wide open to taking advice.