I find I have to be super vigilant. DD generally has one BM a day and if it hasn't gotten into the potty or I haven't seen poopface by 3 pm, I start sniffing her and looking down the back of her diaper every half hour lol. I'll make a game of it or swoop her up for a hug or just take advantage of the many times she asks to be up. Depending on the type of diapers you use, your DD may not be that aware of her elimination, especially if the poo is soft enough to smear in. My recommendation is to work to prevent it. Try to identify any signs she gives for pooping and swoop right in, or see if she has a regular pooptime and watch her like a hawk at that time.