Thanks everyone. It seems that we all know we are appreciated but that as in most things in life - every household is different! Some DC leave food for us to eat, some expect us to bring our own and some say 'raid the 'fridge'!
With my own DC, one always asks us what we would like her to buy in (usually a M and S ready meal, for ease) and the other often asks ' would you like me to get something in or will you bring your own?' so there is a subtle difference, as we then feel we should not trouble her with thinking about our stomachs and bring our own!
When I was a member of a babysitting circle (in days long gone by!) because the sitting nearly always commenced after the children were in bed, I only provided biscuits and coffee/tea etc. However, on the odd occasion where someone sat earlier for me, I would ask if they enjoyed eating a lasagne, or whatever, and ensure I cooked and left it for them, ready to re-heat. Cooking from scratch in someone else's house (few ready meals were available in the 60/70's) is a nightmare if one is not familiar with everything/ovens etc. Today, things are much easier and the selection of ready-meals is such that it is simple to bring or heat a meal in minutes, even in an unfamiliar kitchen.
Thanks for all your input. I was just generally musing on what could be expected - food or not! Mind you, whatever your answer, the sitting itself is usually good fun and my DH says that we should be paying them for the privilege!
Microwave cooking Christmas puddings
Is one's title part of one's name....?