When school starts, my older will be 5 days a week so it is unlikely they will care for her - maybe a stray day or so when there is a school vacation. My younger one will be in 3 days a week full time, but she isn't as in tune with things my parents are saying.
Also this just started. I do think yesterday was a fluke sort of thing. I sat them down last night to get the full story. Seems they were very naughty and my mom flew off the handle - can't fully blame her as I know I have when they get out of control.
Fortunately that doesn't happen too often - it seems to happen when they are bored or have too much time around each other. And this was the case. I gave them a stern talking to - and also a conversation about calling me and asking me to pick them up - that is only to be used in an emergency and I explained the ramifications to me and them if it happens again.