There are a lot of people out there who assume that they are able to drive anyone elses car on a comprehensive insurance cover (as long as the other vehicle is insured). A lot of people believe this because they are 21, or 25, or older than this, but it isn't always on the policy.
When I first passed my test at 17, I was with Quinn insurance, I read the policy and it stated that I was allowed to drive other peoples cars as long as they were insured. This seemed a little silly to me as there was no restrictions as I had even enquired, bearing in mind I was only on TPFT policy as well. After ensuring that what was in the policy booklet was correct, I was then driving around in my dads 600bhp Skyline GTR at 17.
Just because you may have it one year, it doesn't mean you will automatically have it another, it is your responsibility to read and agree to the T&C's, and by taking out the policy you will be agreeing to these terms, if and when the terms are posted, if you read something you don't like, cancel and pay like a £20 fee, I would rather be paying £20 fee than losing my licence.
I agree if you specificly ask on your policy for driving other vehicles, and its not on the policy when you recieve it, then thats their cock up, most calls are recorded anyway so should be able to trace it back. If you don't ask, you don't get, never assume.