I'm an Englishman with friends all over the world, including two from Florida. I've observed both using the word "all" in a manner that appears unique to the area – certainly I've never read of its use online or heard it spoken aloud. The usage is as follows:
Where all have you visited so far?
What all bands are you into?
The addition of the word is quite intentional; it is used to explicitly indicate that the speaker wishes to hear the sum of all possible answers to the question where a word like "other" or "else" would imply a fair selection to be sufficient.
Grammatically I have my doubts about the usage of the word in this context, but it's clearly in use, chiefly (it would appear) in Florida, making the "right/wrong" argument both moot and unnecessary. I would like to know, however, how popular this particular usage is and where (if anywhere) the readers of this question have heard or seen it in use.