We have this problem in the shelters I work with. We are now getting around the problem, but not naming those breeds even if suspected. Like now I have 2 pit bull / lab mixes, but we are advertising them as "Retiriever Mix". We wont mention the pit anywhere.

Its a big problem. At least here most of the companies will still insure you with those breeds. They just require a rider saying they wont cover dog related accidents. i think in Fl they are just looking for any excuse to cancel you.