to tell mil she cannot use xmas batteries

[MadeinScotland2026]

This happened last xmas but it's been brought up again due to everyone making xmas plans i think.

Mil stayed with us last year and she got the kids lots of presents that needed batteries. Which she didn't get before hand or prewarn us that we needed them.

On xmas morning she noticed my bag of batteries I got for xmas and went to put them into the toys she got. I said no they were for the toys santa got ( they were brought for this reason and cost £££)
I told her she can use any left over and I will buy more when I can. She wasn't happy to say the least and then asked the kids which toys they wanted batteries in first ( they said santa which i already knew)
I was annoyed as

1. They cost £££
2. I wanted to see my children play with the toys I got
3. She couldve said before hand or got some herself

aibu?

Agree, come on up spill the beans. The batteries are just a diversion!

Just stock up on batteries
Imagine creating that sort of atmosphere for your kids on Christmas morning, ffs!

How awful of you OP. You should of course have guessed that your MiL would buy a load of presents that needed batteries, without the batteries, and bought extra for this reason, or failing that, made the kids play with the presents they didn't want to and wait to play with the presents they wanted to play with first, to avoid hurting her feelings.

Every parent i know buys a load of batteries before xmas/birthdays for this very reason.
People, (especially those without young kids themselves) often don't think about batteries - it's a busy time of year (!)
Just buy more batteries and make things nicer for everyone. I think you were very rude last year. You could have easily let them put batteries in their toys then swapped them over to use in your toys too.