I'm with Bill 100% on this one. You owe it to your customers and to your peers to do the best work possible, and never allow a knife with a simple flaw to leave your shop. Developing your skills is one thing, selling a subpar knife is just not okay regardless its performance. J said the right thing when he described using his rejects as test knives; that's what I do too. I've learned more by screwing up than I have from those knives that just come out right the first time. I hate it when I have to go back to an early finish step to remove a defect I didn't notice until late, but I'd hate it much more to let laziness become public. I can't count the number of guards I've redone! In my opinion a handmade knife should exceed a production knife in every regard; why else would someone pay a premium? That means heat treat, fit and finish, materials and design. Fortunately for our craft, those who don't have the discipline to do fine work eventually weed themselves out.
As to pointing out to your customers what you perceive as a flaw: not recommended! A knowledgeable buyer will see this before they make the decision to buy and a less experienced buyer will only lose confidence in our work if they are shown the imperfections more than the benefits of superior materials and processes.
In my opinion a knifemaker owes his customers the best he can do, and perhaps more importantly knows that his work reflects on all knifemakers, not just on himself. This is perhaps the greatest contribution of professional organizations like the ABS and Knifemaker's Guild - setting minimum standards of quality.
Now... Just so you know, I'm not perfect by any stretch of anyone's imagination. The FUF loves my shop. I recently sent off a knife and got a call from the buyer a few days later. He said the knife was beautiful, but was there a reason I hadn't sharpened it???

There's no worse feeling than a customer not receiving a product as near perfect as you can make it, and I don't believe you can ever regain the confidence lost from such a stupid error. For this reason I suggest you have the most critical person you know inspect every project before it leaves your shop. Naturally I reimbursed him the cost of sending the knife back to me to be completed, but no amount of sucking up can ever overcome such lack of attention to the basics.