There already is a problem with the card. Units manufactured since late November have a fix, but there are units still out there sitting on store / warehouse shelves with the issue.
http://www.tweaktown.com/news/54774/evga-geforce-gtx-1080-ftw-catches-fire-video/index.html
As for legal obligations of sellers, I can not advise you other than if your cousin buys the card, I doubt the warranty will be transferable. Contact EVGA customer service and tell them your cousin bought you the card for [insert occasion here] and ask ... anything we tell you will not be legally binding; an e-mail from EVGA would be.
Gotta ask, why not buy locally ? Do you save that much money ?