YTA. It’s a house not a Pizza Hut. This example makes 0 sense. Who would ever think that their mom isn’t allowed to drop by?????? I worked in a high powered law firm for over a decade and my mom came by regularly and no one cared. Being a babysitter is even more flexible and doesn’t require a whole lot. You make it seem like OPs children were ever at risk. They weren’t. OP is making it seem like they were somehow at risk or negatively affected by someone’s MOM stopping by for 15 mins to wait for their CHILD to be picked up. 18-21 is considered a legal adult, sure, but if you’re still living at home and depending on your mom for rides, you’re still pretty much a child.

It’s not that serious. OP probably didn’t even do a background check on Gabby or see if she’s CPR certified. She doesn’t even know coworkers stepsister. She just hired her bc OP was desperate for childcare.

It’s the babysitters mom not a boyfriend or something inappropriate. Maybe mom wanted to make sure she could handle the job???? 3 kids isn’t easy for anyone, I’m sure OP knows this as their mom. OP should be less paranoid or invest in cameras inside of the house so she can monitor every single interaction if she’s this crazy.