I have always been a fan of this, at least theoretically. Today was the first time in my adult working life I saw it in practice.
I assumed it would be parents bringing their older elementary or middle school aged children to the office to "see what Mom/Dad does" experience - a time to introduce kids to what the work world was like. I was completely wrong.
It was day care. Freaking day care. Screaming babies. Screaming toddlers. Toddlers running into random cubicles grabbing things off desks. Older children running into people in the hall because their eyes were on their phones and video games instead of where they were going. Parents expecting everyone to coo over and entertain their children. My favorite of the day was the dad with an 18 month old who wandered from cubicle to cubicle asking if anyone had any snacks for his kid. It was a "free day" where nothing got done.
I saw absolutely no educational value for the children in this. I saw no value for employees who did not bring children because work was constantly interrupted. For example, we were having a conference with outside consultants in a closed conference room. The door was opened three times by renegade children on the loose with no supervision and twice by parents who just assumed whoever was in the conference room would want to see and fawn over their child. Seriously. One mom opened the door, walked in, and said, "Hi everyone, this is my baby _____. Isn't she cute? Say hi, ____. Tell everyone hi!" None of us knew this woman or her baby.
I will be sure to schedule field work on this day next year. I like kids. I like babies. They like me. I am a small kid magnet. But I do NOT want them in my office when I am on a deadline and trying to work.