https://www.pcgamer.com/fallout-76-player-who-spent-900-hours-in-game-says-theyve-been-banned/

There's someone out there who loves Fallout 76 so much they've played it for more than 900 hours. The heart is a strange thing. Tragedy has unfortunately struck this unlikely relationship, as the survivor in question has also, over the course their long journey, amassed a ridiculous amount of ammo, so much that Bethesda apparently reckons it's an exploit and they've been indefinitely banned from digital West Virginia. 

Reddit user Glorf12 claims that Bethesda banned them because it seemed so improbable that anyone would play for so long and gather so much ammo. They say that they simply really like the game, and that by using, but not exploiting, the bandolier perk, which reduces ammo weight by 90 percent, they've been able to lug around a great deal.