A woman named Yan, 30, took her 2-year-old son Jayden to a music class at Brisbane's Cream House Premium Cafe, reports Kidspot.
Afterwards Yan had lunch with other parents while Jayden played in the nearby soft play area.
The mum said she "distinctly remembers" making sure her son used the bathroom after his class before he ran off to play.
But just after he came down a slide into a ball pit, her son ran up to her to tell her he had accidentally peed in the playground.
"He was crying so I immediately changed his pants and then he showed me where it happened at the door of the ball pit," she said.
"I got my wipes and went over to the area, apologised to the people around us and wiped everywhere that was wet. It was in the corner and on a plastic mat without any balls around so I thought I cleaned it pretty well."
But before she had a chance to tell the cafe staff, one of the staff members approached her after another customer told them about the incident.
"They asked me what happened, so I apologised and I showed them where it happened, and the guy sprayed the area with sanitiser ... I never tried to hide it or run away," the mum explained.
But Yan was shocked when the cafe's owner told her she had to pay a $50 fine.
"I was so upset, I thought 'That's so expensive!' Jayden had one accident before at Cream House, but it was in the eating area and that was mopped up without anything else happening, so I was very surprised at this."
When Yan tried to dispute the charge, the cafe owner showed her a photo of the centre's terms and conditions - but there was no mention of cleaning fees if an accident happens, she said.
The Cream House owner said her staff regularly clean up accidents without issues.
"Her little boy has peed in other parts of the cafe floor before and it's okay for us because we can easily clean and sanitise it for other customers," she told Kidspot.
"But that day he did it in the ball pit and there was pee everywhere."
Rachel said the extra cleaning would cost $130, and the fine covered $50 of that.
"This is a public area and I have to take responsibility for the other families who come here. I didn't pee in the ball pit but I have to pay for the cleaning. She is welcome to come back to Cream House and negotiate it."
But the mum of one says she won't be back at the cafe after the incident.
"I'll never, ever go back. It's not about the $50 – just felt sorry for my son. He's only two and a half, it's not his fault.
"I don't want this to ever happen again to me and my son."
