My counter example is my sister in law who is very helicopter of her first child, even now that he is over a year old. They've been in small apartments, and have traveled a lot with him in arms(no car, so no car seat). I doubt they have ever used a monitor. I bet if she had had more opportunities to put him in another room to sleep without concern, she'd be more willing to let family play with him in other rooms of my parents' house during holidays.
I think that's a pretty big exaggeration. "helicopter parenting" usually characterises parents who refuse to/cannot step back from their child's life and let them make decisions on their own. A sleeping newborn child cannot make decision on it's own - the only acceptable form of parenting is helicopter parenting when your child isn't capable of doing anything for itself!
Sudden Infant Death Syndrome exists. You can hardly blame people for wanting to protect their child from it.
She was alert when the paramedics showed up, but the subsequent tests at the hospital proved nothing. The cardiologist, nurses, and other doctors all seemed to agree that it was "nearly a SIDS thing" and that we just got lucky.
After that night, and for every night since (2 more kids since then) we've used a breathing monitor. Occasionally I've noticed the kids will go in a "deep sleep", and the monitor will go off a few times during the night, you'll have to reposition them; they'll wince (in their sleep) and carry on. If that's what it takes, then that's what it takes.
From my research after that event, it seems like SIDS is all-encompassing, and the amount of time allowed for an infant to slip into death may play a factor in it's "suddeness".
Sure: baby monitor security is important too: if you can get it right for a baby monitor you've probably got the framework (technical, social, regulatory, etc) to get it right for a bunch of other things.
But are baby monitors themselves solving a problem or causing one? The alternative is to either have the baby in the room with you (distracting: they're like a campfire!) while you do your chores or talk to your visitor or whatnot, or learn to be able to be in another room from your baby.
Sounds luddite, but it helps lay the foundation for a healthy, non-helicoptering relationship with your kid and doesn't slip tolerance for pervasive surveillance into your home.