AITA for allowing my nieces to eat certain foods and not warning my sister that it could happen

AITA for allowing my nieces to eat certain foods and not warning my sister that it could happen

Hi all,

So this week in the UK has been half term week, a week where children have off school halfway through a term. I (M26) am no stranger with looking after my 8 year old twin nieces however my sister (F33) usually provides some form of notice if I need to watch them for a bit, even a couple of emergency times were usually met with at least like 15 to 20 minutes notice however on Tuesday morning my sister drops them off at my flat without any notice whatsoever, just that she was “out”.

I work 4 days on, 4 days off, 12 hour shifts and Tuesday was the first of my four days off. Usually, I spend the first day of my four off exhausted from the previous days of work. I didn’t have a lot of food in the house at that point (I was having a supermarket shop delivered in the evening).

I went to the small shop by where my flat is and got bread to make toast for my nieces and I (they hadn’t had breakfast yet) and two pizzas, the shop had a 2 for 1 price on oven pizzas. I got one plain pizza/cheese pizza and one pepperoni. It was then my sister texted that she’d hop back at 6:15 to 6:30pm to collect her children so had enough food to cover for them (I had a couple of things they could have for snacks in the meantime should they want).

My sister towards November time last year met a new partner, she seems happy with him (M32 or 31 coming on 32)). Her new partner is a vegan and she’s started to adopt that vegan lifestyle, quite full on but that’s her choice. However, regarding her children, I did ask her this at christmas time just gone and she said that at home it’s a vegan first style but at school or round friends houses she’ll allow them to eat non vegan friendly foods

I assumed that policy would also fit with me when I had to look after them. I cooked both pizzas, I gave them the plain pizza and left the other one, the pepperoni one for me to pick/graze at but if they had some I wouldn’t stop them and that’s what happened.

When my sister came back to collect her kids, she saw the boxes in the bin and asked, her nieces said yes that’s what they had. My sister was quite cross with me and said that I should’ve consulted her if this could happen. I did mention that she allowed them to eat non vegan food at school and stuff but she doubled down about how that’s different and she has prior notice. I mentioned that I had zero notice and my sister said that family watching family is different than pre arranged school routines. I don’t know. They’ve only been on their mum’s vegan first beliefs for three months.

If it helps, my nieces mentioned nothing about veganism or vegan food whatsoever, they seemed happy and content when I bought the food and when I cooked it.