We are in a share, and don't leave money (except for a small amount of emergency cash at the house, for use only in emergencies)--it's never even occurred to me to do so. However, we do pre-pay for any activities or classes planned. Expectation is that kids will only be doing those activities (they are all within walking distance) and will be home for lunch/nap--both families prepare lunch and snacks so there shouldn't be a need for treats. I would absolutely not expect our nanny to pay for something for the kids (nor would I expect her to pay for her own lunch or admission if they were somewhere that required this)--but I would also not expect her to plan an activity that required a meal out or admission somewhere new without letting us know. It may be different in a situation where the expectation is that the nanny will be planning activities more freely without consultation with the family, though (and I know it does work this way for some families). With a share and toddlers, we just find it much easier to have everyone just stick with the schedule (Mondays are storytime at the library, Tuesdays are the park, Thursdays are music class, etc.) Your new family may just be used to doing things this way.