Citation: 4A_284/2018 E. B

B.a. Am 7. März 2017 reichten die Kläger beim Tribunal Arbitral du Sport (TAS) ihre Schiedsklage ein mit den folgenden Rechtsbegehren: "The Claimants respectfully requests [sic] the Arbitral Tribunal to: (a) Declare that Mr. A.________ resigned as President of IFAF on 3 February 2015 and that this was accepted by IFAF; (b) Declare that the IFAF Congress held in Ohio on 17 July 2015 in which Mr. F.________ was elected as interim President was the only legitimate IFAF Congress held on that date; (c) Declare that any actions by the rogue-IFAF lead by Mr. A.________ are null and void; (d) Declare that Mr. B.________ was duly elected as President of the IFAF in the Congress held in New York on 17 September 2016; (e) Order that Mr. A.________ cease and desist from acting as and referring to himself as the President of IFAF; (f) Order that Mr. A.________ shall bear all the arbitration costs and reimburse the Claimants for any advance on such costs, including the filing fee; (g) Order Mr. A.________ to reimburse the Claimants' legal fees and other expenses related to the present arbitration." Der Beklagte beantragte die Abweisung der Klage. Am 31. August 2017 fand in Lausanne eine mündliche Verhandlung samt Zeugeneinvernahmen statt. Anlässlich der mündlichen Verhandlung vom 31. August 2017 wiederholten die Parteien ausdrücklich, die Zuständigkeit des TAS zur Beurteilung der Streitigkeit anzuerkennen. B.b. Am 1. März 2018 fällte das TAS den folgenden Schiedsentscheid: "The Court of Arbitration for Sport rules and declares that: