Does Teemo stealth count as "not afk" in aram?

Just a thought that I've been wondering for a while, since I've seen this happening once every few matches with teemo in howling abyss.

In order to make the most out of his stealth passive and the fact that he's squishy, most teemo players tend to remain out of fight until opponents with low health present themselves nearby. In the most extreme cases, teemo players would just watch his team 4v5 and won't participate at all, saying " I'm waiting for the right timing" while remaining still in the bush for the entire match.

How do you judge those situations, since their argument does stand some ground in the sense of playing in a particular way, while at the same time it also holds true that the player is sitting there doing nothing? It gets worse if a teammate decides that teemo is just trolling and decides to walk behind the bush teemo is at; opponents aim their at the teammate, which ends up hitting teemo instead (needless to say opponents immediately follow up because global taunt) and teemo starts saying the teammate is purposely getting him killed - which I somewhat agree because doing so isn't going to help the team, but it's difficult to prove because it's not like the said teammate told the opponents in all chat to aim at him/her, plus tbh my sympathy lies with my teammate since we're all suffering from playing 4v5.

TL;DR - is being in stealth and not doing anything at all, despite claiming it's part of their playstyle&strategy, considered going afk on purpose or not, and if yes how do you prove it when you report? With featured game modes coming soon, some may take place in howling abyss with pick&ban phase, and I see this as an easily exploited troll method.