You need to have a heart to heart discussion with your insurance company. The broker may not fully understand (even though he should) what the difference is between, Certificate Holder, Additional Insured, Additional Named Insured. Each one of these have different implications on your policy and that definition changes between the US and Canada.
Certificate Holder - the safest and you can easily give these out. The insurance company is supposed to inform all certificate holders if there is a change or cancellation of the policy.
Additional Insured - some risk involved. This allows the additional insured party more rights. The insurance company should be very explicit on the certificate for the coverage it is extending to the additional insured. If it is open ended, the result could mean a loss payout for any number of issues. Brokers want to be named Additional Insured because should a carrier make a mistake, they don't want that mistake to eventually come back to the broker. Brokers should inquire with their legal team as to what the certificate should read to extend this coverage.
Example.
XYZ Lease is added as Additional Insured/Loss Payee, but only with respect to the Automobile Policy and their interest as Lessor in the noted vehicle and as per the OPCF 5/5a endorsement specifically for VIN AAA123456789
Additional Named Insured - very dangerous. This will insure the Additional Named party for everything that you are insured for. If you are a fleet this will extend that coverage to their vehicles and any other liability interests. This should only be used for company and maybe a parent or sister company and the insurance company should be asking a lot of questions about this and the relationship between the insured and the additional named insured.
The problem is that the broker is the one that can make these changes without the insurance company knowing about it (at least for some time). Some brokers not very educated about these things and can easily make the mistake between Additional Insured and Additional NAMED insured. In a worst-case scenario, AAA Carrier asks to add XYZ Carrier as an additional insured, but the broker accidently places the wording as Additional NAMED insured and places no specifics. XYZ Carrier can make a claim against the insurance policy of AAA Carrier for any claim that XYZ Carrier incurs. It would put the insured at a lot greater risk and will most likely hold up in court. It's a good reason to make sure you have a great broker on your side.