I haven't babysat a kid who had a poop accident but I was that kid back in 1993 when I was 5 years old and at a babysitters house.
While at the babysitters house I was watching TV sitting on the floor and I needed to poop and so I just pooped my pants instead of going to the toilet.
I also peed my pants as well.
So as soon as the babysitter noticed she took me into the bathroom, stripped off my clothes and gave me a shower.
Then she put my clothes in the washing machine and started showering and bathing me.
After she got done bathing and showering me she got out a Pampers Diapers which was mostly plain white with some sorta picture on the landing zone.
These Pampers diapers were the thick diapers that used tape instead of Velcro and actually those type of pampers were better than today's pampers.
She put me in one of those pampers diapers and then put a shirt on me as well as a fresh pair of socks and then sent me back to watch TV for awhile.
Then she put my shoes on and took me outside to play in her backyard wearing just a diaper, shirt and shoes.
My mom came and picked me up later and I had to walk home a few blocks or so wearing just the diaper, shirt and shoes.
If I babysat a kid and he pooped or peed his pants he would be in just diapers as well.
Every Time I was babysat by that babysitter I had to wear a diaper and so I was babysat by her until 10 years old and wore diapers all the time at her house.
I was dressed like the diaper boy below most times at her house and I loved it.