Sure, plants can be called anything we would like to call them. But if we are going to imply that they have a valid registered cultivar name by writing their name so it looks as if it were a valid registered cultivar name, e.g. if we were to write such a name according to the rules used for the correct formatting of valid registered cultivar names, then the name we use should be, of course, a valid registered cultivar name.
If the plant in question has distinctive characteristics that make it a desirable plant, then optimally it should be submitted for publication and registered as a cultivar, then extraneous descriptive names/adjectives would no longer be as necessary as they seem now and it would be quite acceptable to write the plant’s name as if it were a valid registered cultivar – because it would be.
I am also proposing, though I am not the first to do so, that we use a different formatting when writing these names with the additional non-cultivar descriptive names/adjectives. Most common is to place these descriptive terms in parentheses, double-quotes, brackets, or etc. following the plants correct species name, but not writing the names to appear to be valid registered cultivar names unless they actually are. As an imperfect example; I was once nicknamed “Beege”. If I was introduced to you as “Beege” would you really understand that my true name was William Joseph and that I preferred to go by my middle name, “Joseph”? Of course, I can speak for myself and correct this disparity. So far, I know no plants with this ability. Their names are mostly for our benefit anyways, not the plants’.
I would postulate that even using "Florida red or Florida" as descriptive names would not be the most straight-forward or understandable way to append information to help identify these plants. Keep in mind that many plants and many CP originate in Florida, even other Drosera filiformis. Also, remember that we frequently have new horticulturists joining our ranks and newbie CP growers. What might a plant with an incorrectly written or spelled name do for them? At best it would initiate their incorrect spelling or formatting and perpetuate the inaccuracy.