How would you react (Mil)

Weird but very thoughtful, assuming there was enough food and tea for you too?

You are honoured as
- she and her DM brought everything they needed so you didn’t have to go to the trouble
- she trusted you to do her very specific shop for her
- in 50 years she didn’t go into BiL/SiL’s house

You’re obviously her favourite! She sounds a real character!
???

I would not go to such extremes her picnic sounds like a military operation.
When we visit our daughter we just take a little lunch some times. My daughter will often say “mum we do have food here you know” My husband is diabetic and has a rather rigid diet so I usually take a salad I prepared at home. I take tea bags for me she only has decaf. If my son in law is abroad for work I stay a couple of nights and take ?wine because they don’t drink!

Nanawind ?????

Nanawind, it could be that she turned up everywhere well equipped! I have a friend who's rather like that and brings her lunch with her - and I tend to take Yorkshire tea bags with me (can't stand weak, milky tea)!

Well I would have thought weird but it’s up to her. Same as if I’d been that way inclined when visiting her home. You would be though of as odd though.

Mil is a very unique character.
When we had to start doing her shopping we were given the label/wrappings of everything.
Fruit and veg were only to be bought from a certain market stall. She would know if we didn't.
At the delicatessen we got her 2 slices of roast ham as long as they weren't to big.
And she wanted 2 eggs from the egg lady. (We got 6 and gave her 2)
In 50 years she never went in bil/sils house.

I think that was very considerate of her! As long as you hadn't prepared anything for her yourself?

My mother-in-law and a friend were invited to lunch one time during the early days of our marriage. She turned up with an extra friend as well, no prior notice or asking was it ok.
Fortunately I'd made a pie so I could share it out, but I did wonder what we'd have done if I'd gone with my first plan of pork chops and there weren't enough to go round ?

I would have wondered if she was OCD TBH especially as over a 40 year period she's never had more than 5 cups of tea in your home.

As FarNorth has posted "What's to be offended about?"

They came to babysit and brought their own refreshments and dishes.
Seems very thoughtful to me - they didn't expect you to provide anything and they didn't have to look for plates etc in your kitchen.
What's to be offended about?

(Unless you knew it was because they thought your house was an unhygienic tip.)

They bought themselves a picnic, how lovely, I hope they sat on a blanket and shared it with you!

I would have thought she was VERY odd and would have eaten the pork pie and the cake.

DM = Darling/Dear Mother.

I think I would have been highly amused Nanawind

She turned up with her mother.

Why worry everyone’s different made her comfortable and saved you work
(no idea what she turned up with
DM is a pair of boots in my world)