It's out there. Coming from my time as a middle school teacher, the most egregious example of overparenting I've witnessed was not one of my students, but a student-teacher that I was mentoring and had to fail.
The student-teacher, a 23 year old girl, exhibited the following signs of overparenting:
1. Her parents called her 4 of 5 days of the week to make sure she had ate her sandwich and to see if she liked it.
2. She had her head down down on her desk sleeping one day before school. When asked about it, she replied, "My Mom made me take some cold medicine today. It might be the kind that makes me sleepy".
3. When she was falling behind in her duties, showing up late, coming unprepared, dressing inappropriately (the young boys didn't mind this), who called me to give her a second chance? Yep. Her parents.