It is dodgy. But what they're suggesting is technically the most secure method. You first "sweep" all of your original coins into a new wallet, then your private key for the fork coins is now different to the original's. You can then either input your old private key / mnemonic phrase / or conduct a sweep on the fork coins with the fork wallet. This is still extremely risky because the fork coin developers aren't the developers who developed your original wallet, and they'll have a much smaller operation. This means:
* They could be dodgy and have intended to create the fork in an attempt to gain access to people's private keys. When you use their wallet software, it could simply upload the private key to them.
* Assuming the software is even open source, there will be far less eyes on the code to watch for bugs, or hackers changing code to steal private keys
This is exactly why I'm considering forgetting my Bgold. It's too dangerous and their wallet developers appear either too dodgy or too incompetent. Selling my Bcash was dangerous enough. Even if it's only risking the fork coins, I don't like giving them even the light of day.
Look at the how high the futures price got of S2X before it failed. It's shocking that it got up as high as 0.2 Bitcoins, with such an incompetent and small development operation. People were willing to put that much faith into a fork with such small peer review and extreme developer incompetence that it couldn't even fork. The only way these people learn is by losing money.
