1 Subjective - If same is documented on different threads of Reddit or device forum then NO . Seller cant produce Apple from a Lemon . Not a same corollary but eg the Intel CPUs microcode and Nvidia GPU melting . Its all over internet and someone still buys used from a seller and it happens , Whose fault ?
2 Completely subjective
3 No fault of seller . Buyer supposed to check whether its compatible with own setup . If buyer confirms the setup from seller it will work with his setup than sellers fault as he misguided and he should take it back . Seller can also say I dont know do you due deligence then buyers fault
4.If evidence can be brought forward seller should take it back
For example if i send something and it isnt working or has some defect which wasnt mentioned i will take it back
If you expect my gpu to showcase same temps but they are higher in your system because of you case choice or ambient temps thats not the case i will take it back unless its touching 90 degrees
Small cases have higher temps
A client bought a sony heaset ult 900m sealed pack from me for 4k less than market price and used it for 2 days then say it has hinge issues all over reddit so i should take it back its a NO from me
Do your due diligence before ordering
A guy bought a blackshark v2 pro headet from me and said the voice stutters when he goes to the other room it has small ramge so i take it back
Like man why are trying to wear them in another room? Theres a thing called rcc walls and signals penetration is tough in them
I am not taking a return
About the unboxing video a guy literally returned me a external hard drive by switching the drives inside
I got to know when it reached the service centre
I got my money back by force fortunately
Thats why unboxing videos are compulsory
I have seen people swap serial number stickers aswell on gpus and motherboards just in case the same product they had died