My view is that the terms and conditions of a website, if agreed to by the visitor up front, create a contract
between the owner of the website and the visitor. It can have whatever provisions you want, as long as they do not violate applicable state law.
One question is which state provides the applicable law. Presuming you are in California, the visitor is in Nevada, the website is hosted in, say, Ohio. You may have a number of conflicting state laws involved. However, luckily, must states have adopted the Uniform Commercial Code which talks about waivers of implicit warranties of merchantability, etc. I might need to look into that if you like.
In general, though, having it there is a great start from a legal defense point of view. However, you also have to keep in mind that from a sales point of view, that might be a bit harsh; however, I hear where you're coming from.
As I remember, you are hosting a nanny training site. Is that correct?
I want to point out that the theory of being sued can be different from the reality. For example, if you charge $200 for participating in the site, is someone really going to pay a lawyer $10,000 to sue you over a measly $200. Same goes if the fee is $1,000.
Of course, the fear is that they sue you in Nevada and make you come there. Are there "minimum contacts" with the state of Nevada? (However, it doesn't matter what you put in your contract, they can "sue" you there anyway). Even if you have a forum selection clause saying that all lawsuits have to occur in your county in California, they could still sue you in Nevada, you have to hire a Nevada lawyer to file pleadings in the Nevada case to get the Judge to rule that the case should have been brought in California.
Some states do have versions of the Deceptive Trade Practices
Act, which you should review.
My point is that a good starting point is to put it in there and then go from there. It may or not be technically enforceable, but it makes a great starting point for negotiations.
I guess my point is that you draft your terms and conditions as strongly as you can, but don't expect it all to be bulletproof.