As for wearing any sort of waterproof panties over conventional disposables. I am sure Stacey knows all about that. She is an incontinent woman and not new to any of this.

Plastic panties are fine and necessary over cloth diapers, but seldom comfortable over disposables.

The two solutions I use, and remember I am incontinent, is to always use a modern waterproof sheet to protect the mattress. I use the waterproof sheets made by Secure at home, but to save space when traveling by airplane I use sheets of plastic that fold up very small. Second, I wear a cotton Onesies over either pinned gauze diapers and vinyl panties or disposables. The Onesies hold the diaper comfortably snug and prevents gaps that cause leaks. By the way, in bed poly plastic shell disposables work much better than do cloth-like or pull-on briefs. Onesies help cloth-like and pull-on but they still will leak more than tape-on briefs with a poly plastic shell.