We are hoping to get a weekend in London with dd later in feb, mainly to see a musical, for her birthday.
Money is tight for us, but I can't see us dipping into dds money to cover some expenses, be it food, activities etc, if dh and I couldn't afford it without resenting prices then it's probably something we wouldn't do.
If dd knew money was an issue she'd happily offer her savings to cover everyone's costs, from the age of about four she's suggested buying takeaways for us all when she's known money was tight, or offering to take me for coffee in costa, or topping up the leccy. Whenever we've had to do this, we give her a bit extra back once we've been paid.
So if we were short for an activity in London, and it's something I know dd would love, I'd borrow it off her and give it back next month. I know this is just me, but I'd feel uncomfortable going "surprise we're taking you here for a treat... But you'll have to pay for etc etc" I wouldn't judge others for doing it though and I'm sure you'll have a lovely weekend. I just couldn't do it
myself, as I know if I'd resent paying the prices, I'd resent dd paying it too.
At those cafe prices though, if we really had to eat there, we'd just buy dd a meal and dh and I would grab something elsewhere, he'd really resent paying £17 for a burger and he'd resent himself even more making dd pay for it, there's no way he would pay that for himself though even if dd insisted she was happy to pay it for herself (she wouldn't btw, she'd prefer a happy meal once out of there haha) he'd grumble the whole time criticising the £17 burger and what the money could have been spent on. Hed be looking at other peoples food and oricing it up in his head and acting all astonished. He thinks the price of a Greggs pasty is a pisstake, he'd go to town complaining about a £17 burger. :)