I think this happens more frequently now, because I see a lot more parents 'juggling' the kids. I'm not pointing fingers, this is just my observation. Things are so much more different than even 25 years ago when I had my babies.
Moms and dads are taking turns dropping kids off. Sometimes the kids are divided up between mom and dad. I had a co-worker do this. They ended up leaving one kid at the house while both parents took different kids to practices. When they met up later, neither had the youngest! Luckily, he was patiently waiting at home on the back porch.
A lot of tots spend a good part of their day being driven around, as evidenced by the number of kids eating in car seats. I never let anyone, especially kids, eat in my car. I didn't have them in the car, but a couple of times a day for short trips though. Again, not blaming, just pointing out that kids today maybe spend a lot more time in cars.
I was the only one taking my daughter to daycare. If I went to work, I had to go by daycare on my way there, and back. Once, she stayed home with my hubby on a sick day, and I forgot and stopped by the daycare.
So, I guess, I feel judgmental. I really can't understand how you forget your child. As a mom, that just doesn't compute. I don't consider myself to be an overly cautious parent either; I'm pretty laid back. But maybe I just don't get it because things were different for me.