A certificate of insurance, or COI, does not necessarily extend coverage to the certificate holder. It's just a piece of paper.
The Policy outlines the coverages, not a "cert" as we say in the business. Important distinction, too.
Recently, I was asked for a COI and given the municipalities requirements on a form called an "acord". The coverages required by the city were not on the insured's current policy. Thus we needed to add an "endorsement", and it cost more money.
Here's a trick: It's cheaper to gather the requirements from all your field rental places and other venues, that you know will need a COI, and then approach the carrier at renewal. Get all the right coverages from the get-go.
Adding mid-year pisses you off because you're spending money you didn't budget for, or don't have, and could delay you getting on the pitch.
Added Coverages that I'm beginning to see as Standard for Municipalities:
1. Hired and Non-Owned Auto Liability
2. Excess or Umbrella, sometimes increasing the per occurrence to $5,000,000!!!!
3. Accident and Health, Excess Medical
4. Named Additional Insured by Written Contract
5. Primary and Non-Contributory
6. Waiver of Subrogation
7. Abuse Molestation Liability
Lot's of Big Words, I know... but important as we move into a more litigious age...
So, just because you have a piece a paper, does NOT mean you have coverage. You have been warned.