In Game of Thrones season 7 episode 6, "Beyond the Wall", Jon Snow and several other important characters feel the need to
go ranging beyond he wall to capture a wight.
This is (obviously, and as it turns out) very dangerous. However, in Season 1, Othor's body is risen from the dead south of the Wall, and attacks Jeor Mormont, so obviously the White Walkers' influence works that far.
So instead of going north of the Wall for their mission, couldn't they just have put some already chained corpse next to the Wall and waited for it to be raised as a wight? Even if the Wall prevents that, going 10 meters north of it with a corpse would have been much easier, and
would probably have prevented Viserion's death.
Why didn't they do that instead?
(I understand there might be some thics involved about raising someone from the dead on purpose. That would probably cause problems to Jon, but not necessarily to Tyrion, Daenerys, The Hound, etc., so they could at least have argued over this...)