My mom doesn't just want to pay for meals and events during visits, she wants to give gifts to people. So we weren't too surprised when she announced a spending budget for Miranda during the trip; Miranda was good about that and found something nice to buy that used up the budget.
This happened during the first day; my mom responded by increasing the budget. And she did that in a way that did not impress me: she decided that the way to be fair to her sons was to give each family the same amount of spending money for the grandkids, instead of giving each grandkid the same amount. Everybody else was more or less horrified by this; if I'm remembering correctly, she responded by some combination of covering her ears with her hands and telling us that we can't tell her what to do.
I raised the issue the next day as we were walking to the car, saying that I really hoped that she wouldn't say things like that to the grandkids on the other side of the family; she responded by calling me stupid, spelling it out just in case I didn't get the point.
I don't think that she actually treats her grandkids that way normally: I've never gotten the feeling that Miranda gets more Christmas / birthday gifts than the other grandkids.