when i was a grad student we had to complete online training courses on ethics in research involving human participants every couple of years for our lab to maintain IRB approval. i don't exactly remember every single detail from those courses but i have a very hard time wrapping my head around how most of the shit that i hear about getting pulled on mturk squares with that
The worst was that economist who wanted to see 'how low we'd go.' (Literally, his hypothesis had something to do with how little you could pay someone to do something that they'd find offensive (ethically). So, some folks would get to write a nice letter to an inmate: Go for it!
Others would get a pedophile. (Keep your head up, child abuser??)
Then, he'd ask you to tag photos of puppies
Or, horrible (trauma invoking - not just cuts -more like decapitation stuff) photos.
It was the most unethical thing I'd ever heard of.
A few people reported nightmares afterwards. Folks with trauma, already, reported flashbacks.
Totally unethical.