My advice to you is to play the game as if all pokemon who are capable of having Natural Cure have the ability. There's no way for people to know your pokemon aren't Natural Cure ability if they are capable of having it because of the lack of an ability activation message. Besides, the main pokemon who have Natural Cure are Blissey and Starmie. Natural Cure is the most popular ability among these 2 pokemon so I would just spore another pokemon even if they switch out. One of my Starmie has Analytic and if somebody put this Starmie and another pokemon to sleep I wouldn't be mad because there is no way for them to know that it is not Natural Cure. Staff may have another opinion but I have been playing like this for a while and have had no trouble yet. Gl and hf in your game.
But most of people who truely have naturecure Blissey and Starmie and have been spored first, when their another poke also has benn spored, they are just still arguing in the battle channel and saying they will report if their opponent don't disconnect immediately. So that why I want GM can make a detail definition. Detailed rules can reduce people arguing with this rule. If we can't spore another poke even the first poke we spore has the naturecure ability, or we have an exception, please write it down! :confused: