The relevant Florida codes can, it seems, be found on pages linked from this index.
Section 61B-45.020 (Defaults and Final Orders on Default) provides that:
(1) When a party fails to file or serve any responsive document in the action or has failed to follow these rules or a lawful order of the arbitrator, the arbitrator shall enter a default against the party where the failure is deemed willful, intentional, or a result of neglect. ...
(2) Final Order. Final orders after default may be entered by the arbitrator at any time. The arbitrator shall receive affidavits as necessary to determine damages.
(3) Setting Aside Default. If a final order after default has been entered, the arbitrator may set it aside for reasons of excusable neglect, mistake, surprise, or inadvertence. A motion setting aside the final order after default must be made within a reasonable time not to exceed 1 year after the final order was entered.
Section 61B-45.043 (Final Orders; Appeals; Stays.) provides (in pertinent parts) that:
(1) Unless waived, a final order shall be entered within 45 days after the hearing, receipt by the arbitrator of the hearing transcript if one is timely filed, or receipt of any post-hearing memoranda, whichever is applicable. The final order shall be in writing and shall include a statement of any award or remedy. Failure to render a decision within such time period shall not invalidate the decision.
(2) The final order shall be mailed to the parties, if unrepresented, or to their counsel or other qualified representative of record by regular U.S. mail. The final order shall include a certificate of service which shall show the date of mailing of the final order to the parties. The date of mailing of the final order shall be the date used to calculate the deadline for appeal by trial de novo.
(3) The final order shall include notice of the right to initiate judicial proceedings under Section 718.1255 or 719.1255, F.S.
(4) The decision shall be final and binding upon the parties, unless judicial proceedings are initiated pursuant to Section 718.1255 or 719.1255, F.S.
(7) A final order of the arbitrator does not constitute final agency action and therefore is not appealable to the district courts of appeal as otherwise provided by Section 120.68, F.S., and Rule 9.110, Florida Rules of Appellate Procedure. Appeals, if taken, shall be by trial de novo as described in subsection (4) above.
A trial de novo starts from the beginning, and does not rely in any way on the decision of the arbitrator, whether by default or after a hearing. However the deadline for filing an appeal is limited and strictly enforced. Failure to file an appeal within the time limit means that the arbitrator's decision becomes truly final.
The Florida Bar Journal article "Navigating the Nonbinding Arbitration Minefield in Florida" says:
The arbitration decision is final unless a complaint for a trial de novo is filed within 30 days. The Fourth District ruled that the 30-day rule is a strict deadline in that the five-day mailbox rule does not apply when computing time. The party moving for the trial de novo has the initial burden of persuasion with respect to the litigation. If the party moving for a trial de novo does not receive a more favorable result at trial, such party shall be assessed the other’s costs, including attorneys’ fees. (citations omitted)
So it appears that the arbitrator's decision carries no weight as such, but may affect the award of fees and costs.