Now you know why lfr is a thing.
Even if the Achievement is Real, doesn't mean they didn't pay a Mythic guild to let them Die in a corner for a heroic Kill.
No, it's not. There is nothing - and never has been anything - unethical about buying a carry as long as it happens with ingame gold and without someone else playing your character. You are paying others for having put in the effort to learn the fight and taking you with them - nothing more, nothing less.
Do quick armory check, there is an addon which provides armory link.
Even ppl with mutiple kills sucks so it doesnt matter of they have achivement or not. I am using fake achivement a lot because it's the only way to get into pug groups.
I was mythic raider and can't raid on guild anymore because i can raid every 2 weeks not every week and there is no guild that will accept it during progress.
Heroic difficulty is like dungenons for me. Fails? Everyone fail sometimes but in heroic it's very rare that i fail on any mechanic even if it's new raid but in pug raid Item Level and Achivement is EVERYTHING. It's actually better to have random items than items woth better stats but lower ilvl because it wll let you get into raid easier.
Ofc 920 ilvl player with set bonus, good legendaries and trinekt will do bettter dps/hps/surive logner as tank than 925 player with random items wrong legendaries, no set bonuses and bad trinkets but for pugs 925 one is better
Join a guild. Fake Achievement addons are probably the best thing ever.
The best you can do is using an addon to get an armory link, or using something like WoWProgressLink to view WP or Raider IO. Neither site will be able to tell you if it was a carry or not, though. But the addon solves your problem.
"Hope can turn into despair in a heartbeat."
R.I.P Chester Bennington 1976-2017