I can't imagine Jen would be playing if/when she went shopping that day, simply because of the drain in the battery.
This is only what I do btw, if I may need to make a call (or several) about something, I try to preserve the battery for the things I need that day i.e. daughter's dress. My phone would be on all day and used for things I really need that day and fully charged before I left home.
I don't think my battery would last over 24 hours of being called and then "pinged" the next day especially as iPhones have an awful failure to ANY moisture.