Eleven Mistakes of the wayward Time Traveler.
Number 1: Gold and Goblins.
Have you had enough of this bland, boring existence in the future, and thought a nice and permanent vacation to the past is where you ought to be? Do you have a trunk packed full of ten sacks of Galleons, enough to empty your family vault? Wait right there!
This, my friends, is Mistake Number 1; bringing back duplicate gold.
Ah yes, I can hear you now, frowning and murmuring duplicate in mingled confusion, but this is among the most common err of the wayward Time Traveler's journey, and allow me to explain how in the following tale.
"What do you mean, you won't accept it?" Harry demanded of the squat, one-eyed, fang-toothed goblin behind the desk.
"Exactly what I've said, Mister... James Evans Peverell Black. Galleon serial-number 64711202-011, currently held in the Lestrange Vault #4. How, precisely, have you come by an exact copy?" The goblin inquired.
Harry frowned down at the vicious creature and crossed his arms defensively. "I don't know what you're talking about. That Galleon has been sitting in my trust-fund vault since the time I was born," he defended.
The goblin leaned forward and stared at him. "And when, pray-do-tell, were you born?" It asked in a dangerously quiet voice. Harry grimaced and reached out to take the gold back, but in a moment the goblin had his fingers in a delicate and decidedly painful grasp.
"I do not believe you, Mister James Evans Peverell Black. In fact, I dare say you have been down into our vaults under another name, and are exceedingly foolish to return to this branch and try to re-invest our own, stolen, gold." It stated in that same quiet tone.
Harry tried to tug his hand free to no avail, and a bead of sweat dripped down from his hair and into his eyes as he was dragged closer. "Shall we send a team down to investigate and confirm? Of course, there are other possibilities... far worse possibilities... than breaking and entering. I would pray toward the former, were I you."
Harry felt pain surge up his arm as the goblin twisted his fingers, and a moment later a small hammer had appeared from beneath the desk to wallop him upside the head. His last, anxious thoughts of the next ten years, were of what had gone wrong with the journey after such a short time.
A simple if sufficient demonstration, my friend. While this uninformed mistake may not always see you sealed into a vault for ten years, it may instead see you delivered to the dragons down below, tossed off of a rolling mine-cart at upwards of a hundred feet per second, or worse still, turned over to the Unspeakables for violating the Unspokenlaws.
You could, of course, spend it haphazardly rather than try to invest it, but sooner or later these repeated Galleons, Sickles, and Knuts, are going to work their way around. You might very well be responsible for the Great Gold Depression of 1946!
So take care, and melt your gold down into the equivalent muggle styled bricks beforehand! Good luck, and be sure to check in on Number 2; Re-Sorting, in due time.