Everyone should read and understand their insurance policies. Insurance is complex and unless you're well versed in contract law you may need to ask for explainations.
If you still have questions ask an attorney or most states have a Department of Insurance with websites that can explain what all the common insurance terms mean.
It is best to get everything in writing for any transaction, that way there can be no misunderanding by any party to the transcation.
I'm not inclined to think that USAA (or any insurance company's) agents lie to get you off the phone. I think it is usually just a misunderstanding.
To give an example of how complex it is you say the USAA agents lie when handling claims. Agents don't actually handle claims, they are on the sales and underwriting end, not the claims end. Adjustors are on the claims end. These are tiny details, but insurance is full of tiny details like that.