I recently looked into this issue for a group that I am a part of. I believe that while the statute may be outdated and may disagree with the state attorney general's opinion, it is illegal within the State of Florida if you have to wager or pay to participate. If you don't have to pay to play, it should be ok. The reality is that thousands of Floridians do play fantasy football and they don't get arrested. I can't tell you to play or not to play, but I do think it is illegal.
The US congress has claimed original and exclusive jurisdiction over internet gambling in 31 USC § 5365. The subchapter that controls internet gambling is 31 USC subchapter IV, starting at § 5361 - § 5367. In this section, internet gambling is disallowed but there is an exception made for fantasy sports in § 5362 1(ix). Fantasy sports are allowed provided that they follow the following rules:
(I) All prizes and awards offered to winning participants are established and made known to the participants in advance of the game or contest and their value is not determined by the number of participants or the amount of any fees paid by those participants.
(II) All winning outcomes reflect the relative knowledge and skill of the participants and are determined predominantly by accumulated statistical results of the performance of individuals (athletes in the case of sports events) in multiple real-world sporting or other events.
(III) No winning outcome is based—
(aa) on the score, point-spread, or any performance or performances of any single real-world team or any combination of such teams; or
(bb) solely on any single performance of an individual athlete in any single real-world sporting or other event.
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Fantasy sports, including daily fantasy sports, appear to be perfectly fine in Florida -- all of the major sites like DraftKings and DraftStreet and the like service Florida as well. The general consensus in the fantasy sports community is that they are both acceptable in Florida and federally under the UIGEA exemption. For a formal legal opinion as to why this is the case, or whether your particular idea would qualify, you should consult a gaming attorney familiar with daily fantasy sports. This is not advice as to whether or not you should play in these leagues, just a general observation on the prevailing viewpoints per your question. If you want more detail, you're going to have to pay for an attorney. Best of luck.
I focus my practice on (video) gaming industry, casino gambling, and complex internet law issues, electronic free speech, entertainment law, copyright and trademark law, and computer fraud. I primarily represent game developers and founders of emergent internet technologies. The author is a Maryland attorney; however no answer given on Avvo is intended as legal advice or intended to create an attorney-client relationship.