If you take the position that 3rd party addons are against the rules of the game then ANY use of 3rd party addons is cheating.

I personally feel that they are cheating because it is against the rules of the game and as such will not use them. That is MY choice and opinion.

That said I cannot know what someone is running on their computer unless they are stupid enough to broadcast it in video or talk about it in chat. It is a don't ask don't tell system. However if they harass someone with the addon you can bet I will report for harassment. Otherwise none of my business what they are running.