Yes, she could have gone ahead and fitted them not knowing the client was pregnant.
But the FACT is the OP now knows the client is pregnant, prior to fitting.
Even if the client only revealed the information immediately prior to fitting them, they must not be fitted otherwise you will invalidate your insurance.
This is not a grey area in law. It is black & white.
To carry out a service against the advice of your training company or product supplier is reckless at best.
You can't offer the defence of ' Well it didn't cause me any harm m'lud'.
Yes, chances are it will all be ok and money in the bank. But, there is always the one client who will react badly. The more times you take the risk, you increase the odds of it going wrong.
Plus, the lawyer representing the client will find this out and will use this information to demonstrate to the court that you are a habitual risk taker and it wasn't simply a one-off minor error of judgement on your part.
Maybe you need to watch some more episodes of Judge Judy.
That was a joke...