I received the email saying that my 31 will be going into production soon and do I have any questions. I mentioned the issues discussed here and referred them to this thread.
Here is their reply.
"We have not changed the design of the Sebenza 31. Lock rock, or vertical blade play, is when a lock begins to move vertically. Unsafe vertical play happens when a lockbar isn't fully engaging and there's a little space between the end of the lockbar and the tang of the blade. This isn't the case with the Sebenza 31.
When applying force to the spine of the Sebenza 31's blade, you will feel some vertical movement. Rest assured, your lock-up is secure. This movement is the lockbar flexing in response to pressure, though the ceramic ball, acting as a fulcrum, will maintain its position against the blade tang. It is very much a sound lock and when put to the test, proves stronger than the heat treated lock on the Sebenza 21. All of our models with ceramic ball interfaces have varying degrees of lock flex so this is not abnormal, though the Sebenza 31 seems to be under extra scrutiny as it is the newest.
All that being said, we do take customer feedback seriously and appreciate you relaying your concerns. If you feel comfortable giving the knife a try, we would be happy to continue with your order. We do have a return policy, as long as you do not use the knife and contact us about a return within 2 weeks. If you would like to cancel the order, please let me know."