Well she is not paying income taxes for one. She is breaking the law by coming here for two. You are violating the law by hiring her for three. Then I guess you got to worry about the fact that she might realize how much your kid is worth on the black market, because it's a lot more than you're going to pay her. Of course, if she did decide to do that, you can't really track her to find your kid because any bank account, credit card, or trace of her is someone else's stolen identity. Those are just a few reasons I can think of as to why that might be a bad idea.
Okay, the income taxes I'll concede, even though that's not a particular concern of mine.
I'm discussing the state of law, and what should be the law, so saying it's illegal is beside the point of my question. The risk I take with my kid is mine to assess, and mine alone.
So, your point boils down to, "She doesn't pay income taxes." A citizen who made that little wouldn't pay taxes either, but for argument's sake, let's say I pay a tax or fee to the government for using an undocumented worker.
Now what is your objection?