I've just remembered one time he told me of a customer who came in to see if he could better his previous years insurance. When reading through the t&c he asked the customer whether he was aware that his comparison site policy didn't cover him at night because he'd only had his licence a few years.
Only found in the small print, not clearly highlighted.
It's a fair point, I've said many times that for anyone with unusual policy needs, such as the very young, old, inexperienced, lack of NCD, poor driving record, etc., consulting a broker is often the best option.
For the rest of us with with simpler insurance needs, there's nothing wrong with using comparison sites. Insurers don't concoct special stripped down policies for these websites, they are all standard internet policy offerings - and you must be issued with a statement of particulars which details the levels of cover, and any onerous conditions, clearly.
Black box curfew policies are available on the comparison sites, but you had to opt-in to have them included in the results when I was looking at insurance for my eldest. I fail to see how you could buy one of these policies by accident.