oh, playpens and cots didn't stop my mountain goat of a DD from 18 months onwards, she could climb out of cots and over stairgates (thank fuck DH was there to see her do that one and catch her!).
Some DCs are easier to contain than others, DC1 didn't manage to climb out of his cot until he was more like 2.5, twas rather a shock to have a little Houdini child after a normal one...
Honestly, some people are really weirdly relaxed about their bodily functions and will happily shit and piss infront of their partner and anyone else, most people don't feel this relaxed, so if they are having to have an audience, it might be worth thinking they've tried the alternatives, and this is the least bad option.
The "my child never sees me wee, you just arent being good enough parents" types do sound rather like the "don't be silly, your child will sleep through by 8 weeks if you are just disciplined enough to stick to a routine" types (Disclaimer - my DC1 slept through at 8 weeks, I thought it was down to my parenting, parented DC2 the same way, we're a couple of years on and we're still not consistantly getting a full night sleep, but since she's been getting herself out of bed since 18 months and just toddling into our bed without always waking me up, its not as bad as it sounds!).