In my country we have a simple rule to prevent electioneering on election day: electioneering on election day is forbidden. Not 100ft, not 100m, simply nowhere.
Same in my country. Elections are always on Sundays and the campaign stops from Friday night to the results reveal at 8 pm the day of the election. Spreading polls results or estimates is also forbidden during this period, even though in recent years it has been hard to enforce especially from foreign sources.
Not sure if that is what you are referring to but this is what happens in France with Swiss and Belgian websites being overloaded on French election days.