Yeah, I've heard about kids not crawling. I actually basically taught both of mine to crawl. Just kept working with their limbs and encouraging them until they figured it out. Of course, it's a double edged sword!
With one kid, it was easy. We didn't even have a baby gate for Phil. We had a door at the top of the stairs going to the basement. And he was never left alone on the second floor. The only risk was going up the stairs from the ground floor. But if you let a kid get high enough to fall back down, without you noticing... you've really messed up. We let him climb the stairs as he wanted, and just caught him if he fell. And everything else was babyproofed.
But camping was a whole other matter. Poisonous mushrooms, or even eating leaves and pine needles, or dirt... Or sleeping. Maybe we should be high-class and bring a hardwood knock-down crib with us.
With Elise, it's much different. Phil is 4, still needs some attention, and Elise loves to get into his toys (danger!). And it's a different house. Bungalow, no door at the top of the basement stairs. I actually made my own baby gate from scratch so it looks nice.
So, she's 9 months now, crawls all over, and is starting to pull herself up on the furniture. And of course, camping, puts anything on the ground in her mouth. Nor would I leave a baby alone in a tent to nap during the day, rooftop or not. We don't use the playpen in the house at all. It's just for camping, cottage, or the babysitter uses it as a crib.
I think the obvious answer is that the person who made the comment, has no kids. Or leaves them at home.