I have not used EZ Car Rental but I did notice in their terms and conditions (also L&M Car Rental and Payless Car Rental) that they reserve the right not to rent to you if you decline their insurance and coverages and also do not prove you have equivalent coverage on a car you own back at home that extends to any car you drive.
I suppose that most of the time they won't be pushy but if it is a busy week like Daytona Week or if they anticipate a shortage of cars possibly due to overzealous booking on their part they might press this issue.