Yeah, I did it and brew up some 10,000$ class demo account deposit. It happened when I was checking the scalping and made my way of a short loss hiding by getting 1000$ profit each day (10% total profit) and it was the two bad WIFI connectioin failure. I left it whole night and Gold brew up and lost 5000$ in SL and another time was OIL.
I'd say the smallest ammount could be the good confidence building for the newbies in the REAL account. There would be the hardware side failure and a sudden slipping down of the price without any reason to happen. It's not normal but the worst thing could happen any moment. If you do it good from the first couple trades, then it would be the same with the same method in the common sense. Some people would decide to see what would happen as the human error and learn to reduce the risk by not trading too much. A newbie could go with the normal deposit like DEMO, but the real money would hurt more for the psychology with the real losses. It would be better for the newbies to check if their strategies work as they did in DEMO like scientists rather at the first few tries than be as traders to aim for the profit. Test few times and then the real money to be spinned would be a science model.