Ms Stoff said the woman "went out of her way to come back with her child and yell at us". "Entitlement these days is real," she wrote.
"They even got mall security because we said they couldn't pet the working dogs. Security said that the lady was crying. So much harassment for just saying no."
In the video, the woman can be seen arguing with Ms Stoff and the owner of the company. "That was very rude how she definitely talked to me," she says. "You should have a sign."
The owner can be heard saying, "It literally says 'do not pet' on every single dog. There are like four signs."
The woman hits back, "She should not say, 'No', she should say, 'Sorry, these dogs are in training.' That could have been nicer. She could have approached it nicer."
The owner responds, "You asked the question, 'Can I pet the dog?' and she said, 'No.'"
The woman complains that "she could have said they were in training".
She then realises she's being filmed. "You are recording without my consent. It's illegal. I'll call my lawyer right now," she says.
Ms Stoff hits back that "it's illegal to harass service dogs".
The video was posted to Reddit forums including r/PublicFreakout and r/EntitledParents, where it attracted thousands of comments.
One user suggested a nickname of "Service Dog Sally", putting her in the esteemed company of Cornerstore Caroline, South Park Susan, Hallway Hillary and BBQ Becky.
"I think she is mad someone had the audacity to tell her special snowflake child 'no'," one person wrote. "I feel sorry for the teachers that have to deal with that mother."
Another added, "When are people going to learn that 'no' is a complete sentence."
One user described her as a "moron". "Now she is going to be plastered all over the internet and the butt of a new joke," they wrote.
"How does anyone convince themselves they're right in these stupid situations? How can your head be so far up your own ass, you convince yourself you are entitled to pet any dog you want regardless of what the owner says?"