I just got back from a flight and thought I would share my experience.
I showed up at the airport already in diapers and wearing a onsie (with plastic snaps luckily) under my normal cloths. In my bag I had extra diapers, onzies, wipes, plastic pants, small roll of trash bags, and a pair of thick training pants. When I went through security, I had no problem with scanner or anything like that, but my book bag did get flagged for search after going through the X-ray machine. The problem ended up being the roll of small trash bags. She asked if I had any liquids or lotions in my bag, which I said I didn't. When she found my dinosaur print onsie, she asked if they were my pajamas. Not wanting to elaborate, I said yes. She said they were cute and searched the rest of the bag. At this point I was just a little embarrassed so I focused on putting my shoes back on. She found the trash bags but searched through the rest of the bag looking for other liquids without any more comments. She took the trash bags out and ran them through the X-ray in a plastic bin separate from the bag. The TSA agent did have a small laugh with the X-Ray operator as I waited, but i couldn't hear what they were talking about. I was given my bag back and everything and was on my way.
On my return trip I placed the roll of trash bags in the bin with my shoes and didn't have any problems.