Why would someone get a ticket for no proof of insurance when she is insured?

Any number of reasons, 1 the driver was excluded or otherwise not an insured under your policy. or 2 insurance proof was not furnished in a form of writing when requested by the law enforcement officer.

Answer"Why would someone get a ticket for no proof of insurance, when she is insured?"

In most states, you are required to provide proof of insurance if stopped by an officer. If you cannot furnish a current insurance card he has the option of issuing a traffic ticket.

Normally you can take a notarized letter from you insurance carrier to the clerk indicating coverage for the driver was in effect and the ticket will be dismissed.

However you state in your post that your wife is excluded. If a person has been excluded from the policy she is in fact driving without insurance.