The prohibition is on using (and owning, I think), not holding wands. You can put wands in your Gringotts vault, ask an House Elf to bring you your wand, … but goblins or elves aren’t allowed to use wands. If they try to do it was a borrowed wand, I doubt it would go unnoticed for long. There is “priori incantatem” to check how a wand was last used for, and there may be global spells like the Trace that will warn the ministry if a magical creature uses wands.
The prohibition is on using (and owning, I think), not holding wands. You can put wands in your Gringotts vault, ask an House Elf to bring you your wand, … but goblins or elves aren’t allowed to use wands. If they try to do it was a borrowed wand, I doubt it would go unnoticed for long. There is “priori incantatem” to check how a wand was last used for, and there may be global spells like the Trace that will warn the ministry if a magical creature uses wands.