Have You Ever Been Duped Into Doubling Your Money?
No, but I once added some fiat (not much) to a trading platform where I could play with leverage and ended up not being able to withdraw my profits (or initial investment). Turned out they were crooks, but the platform seemed legit at first. So I guess that's worse than losing on Forex, but at least with small amounts. I both won and lost on Forex too in the past, btw, overall probably broke even.
I think getting duped can be hard. However, knowing they you might get duped and still didn't choose to do your research and still get duped, I think that's probably the height of it.