The issue now is that the employment laws are so nasty in places like NYC that a scammy nanny can financially wipe you out with zero evidence.
That doesn't happen with a dog.
I live in NYC and have heard this cited as a concern precisely zero times. Besides, a ton of people use daycares, not nannies.
Laws just changed. This will become more common. Similar to how NYC paid out 500m to a collection of some legit and many scammy 'police misconduct' lawsuits.