The nickname is narrower than the rule it describes. Ohio defines all three excluded categories. A professional athlete is one "who performs services in a professional athletic event for wages or other remuneration." A professional entertainer performs "in the professional performing arts ... on a per-event basis." A public figure is "a person of prominence who performs services at discrete events, such as speeches, public appearances, or similar events ... on a per-event basis." A touring band and a keynote speaker sit inside the same clause as a linebacker, so a page or a headline that treats this as an athletes' problem is describing a third of it.
The relief being withheld is an employer withholding rule, which is worth stating precisely. R.C. 718.011 addresses whether an employer must withhold municipal income tax, not directly whether the individual owes it. The practical effect for a visiting athlete is nonetheless immediate: withholding starts from the first day rather than the twenty-first, in every taxing municipality on the schedule.
The hard question has never been whether the city can tax, but how much it can reach. The Ohio Supreme Court answered it in Hillenmeyer v. Cleveland Board of Review in 2015, in the case of an NFL linebacker who played one game a year in Cleveland and was present for two days each time. The court held "that although Cleveland has the right to tax the compensation earned by a nonresident professional athlete for work performed in Cleveland, the city's application of its games-played method of allocating income violates the due-process rights of NFL players such as Hillenmeyer."
The whole argument is about the denominator. Cleveland allocated by games played, so one game out of roughly twenty put five percent of a season's pay in the city. The player's objection was that his compensation covered "the training, practices, strategy sessions, and promotional activities he engaged in" as well as the games, so a game-based fraction taxed days spent elsewhere. The court agreed: "Due process requires an allocation that reasonably associates the amount of compensation taxed with work the taxpayer performed within the city ... By using the games-played method, Cleveland has reached extraterritorially, beyond its power to tax."
Duty days is the method the court accepted, and the record shows the size of the difference. The numerator is days spent working in the taxing city; the denominator is all days the job required. Hillenmeyer had "157 duty days in 2004, 165 in 2005, and 168 in 2006," which produced Cleveland allocations of about 1.27, 1.21 and 1.19 percent against the roughly five percent the games-played method produced. The opinion also recorded that "except for Cleveland, municipalities that have chosen to tax professional athletes do so on the basis of the allocation offered by Hillenmeyer, the 'duty days' approach," so Cleveland was the outlier rather than the norm.
Two dates that will otherwise contradict each other. The version of the Ohio statute at issue in that case gave a twelve-day grace period, because the tax years were 2004 through 2006. The current section, effective March 23, 2015, sets the threshold at twenty or fewer days. A reader who takes the number from the case and the rule from the statute will publish a contradiction. Note also that the exclusion of athletes from the grace period survived the constitutional challenge: only the allocation method fell.
How many places do this is not a question with a citable answer. There is no federal registry of state or municipal income taxes, no requirement that a city announce a policy toward visiting performers, and the position changes with local ordinances. The mechanism is the durable part; a count is not.