A few years back a friend of mine was depositing a $300.00 check at Chase. When the teller asked him how she could help he said "Oh, just depositing this three thousand dollars." She punched in the deposit for $3000.00 and gave him a receipt. It was corrected within 24 hours but the receipt and printout of his bank statement was a great conversation piece. I doubt they would have let him just walk away with the money, nevermind multiple times.
You have to type in a number. So if you are going to type in 1000, it would probably more likely be a successful attack if you actually forged the check so it looked like it said 1000, so again not seeing how an adversarial example is helpful here.
Humans are harder to fool. But some bank apps allow you to deposit a check by photographing it. Such apps would be fairly easy to attack.
If you limit yourself to making 100$ checks become 1000$ checks and not 1,000,000$ checks, you might even get away with it.