Some of the issue is that YCS does not actually stock several (or many, or even all?) of the items they sell. The use a "drop shipping" method, in which your item is shipped from a distributor directly to you once it is ordered.
Due to the fact that their inventory is not local (but in a warehouse somewhere else), YCS cannot tell you for certain if an item is really in stock with certainty if the inventory becomes low. I have had 2 instances where this has caused me headaches, and it took over a month to get my credit card refunded by them in one case.
Since these experiences, I do my best to deal only with e-tailers that have actually have the knives they sell at their location. That way they can inspect the knives before shipping, if needed, and can vouch if something is actually in stock by way of a simple phone call.