I see nothing in this story that is implausible. Odd and unusual things happen all the time. In fact, the unusualness is what makes the story. I really don't get why people want to jump all over people's odd experiences an declare them "totally fake bra, you wouldn't dare be nice as a service employee", or maybe "in your job where you are dealing with hundreds of strangers a week, not one of them (or some of them) could have been an unusual case". It's like saying: I have a raid 6 at home. It's never lost data, and not one of the hard drives ever failed, Backblaze must be lying about the part where they have hard drives fail.
If you think teachers having kids role play the lives of other people is so crazy as to not have happened, I'm not sure what to tell you. I know that when I was a kid, one of the summer camps I went to did similar things. One year it was just live your day in a wheelchair. Another year it was role-play the lives of a very poor family, and have figure out how to handle a broken arm in one of the kids and still pay rent, eat, etc. These included going out into the world, not just staying in the camp.
I've heard other people who in school had to wear "pregnant suits" or carry "babies", or go around with blindfolds, and so on, to help them understand the situation other people may be in.
Perhaps it's the part where a mall worker runs into someone in another part of the mall later that day. I'm not sure how this even comes close to improbable. I've run into clerks who helped me in the food court before.
Overall, I'd rate this story as Extremely plausible. No single element of it is at all sketchy. Some of the coincidences are less likely to happen, but again, not even deserving of a rating rare, merely unlikely.
If the story teller had a 100 stories like this I would be more suspicious, but a single event that is unlikely is pretty believable.