NDAs aren't worth the paper they're printed on (or the pixels) UNLESS you have the money to spend on legal muscle.
And even then, you can easily dump loads of money on lawsuit and win little to nothing back.
In our local playtest design group, we have private teams of people trusted by designers and then public playtests when the game is ready to go to press. Several published designers shrug off the IP theft issue because the amount of effort protecting designs isn't worth the end result. They've told me horror stories about the Chinese market where you can find barely reskinned versions of many successful Western games and the designers never see a dime. Even worse, a couple designers say that their own printers in China are cranking out extra copies and selling them on Amazon in the USA. They proved the issue by showing how Amazon had brand new copies being sold by 3rd party sellers, but the designer was selling the game directly so nobody should have any new copies except the designer.
until he denounced me for being za'akier.
How dare he say that!!!
That's an insult to za'akiers!!!