This. Duped items are actually safe. Doing the duping, however, is incredibly risky. I've built computers in the past. There's a reason why you should let computers shut down safely and not just randomly turn it off. You can corrupt the data on the hard drive. The same is true for video games. This is why many video games tell you not to turn off the game when it's in the middle of saving.
I haven't heard of any sort of hacked items or anything else similar to the things that broke WW and CF yet. I think this is just rumors right now. If people lost data, it's either because they were duping, trying to dupe, or the game corrupted for some other reason that had nothing to do with duping (accidentally turning the game off during saving, your game cartridge got a small error/corruption in it for no reason - this happens even with computers sometimes for no reason but it's rare, etc).