Using 3rd party tools to call out Box Spawns / Enemy Buffs / DR considered cheating?

[Bartleby]

Yesterday I had the displeasure to watch someone streaming Feast Solo queue openly use a 3rd party program to call out when boxes spawned as well as when players used certain buffs (e.g. bot calls out 'Player A just used Blood for Blood'). When I confronted him about this he replied that he doesn't consider it cheating and that "lots of people do it", "no one ever cared when I did it on stream before", and "it's fine to use in raid, why wouldn't it be fine to use in PvP" to paraphrase.

It's upsetting to know that someone who is currently ranked in the top 4 on my datacenter has probably been using this program the whole time to gain an advantage over everyone else they've been playing but I'd like to open up the discussion to everyone else; do you consider using 3rd party tools like this cheating? If so, how can we fix it/is there anything SE can do to stop them?