Preordering is always a bit scary, just like buying stocks.
When you buy stocks, you do it only when you are confident the company will produce in the way you expect. The best way to come to that decision is to investigate the company before you buy.
If you decide that the company is a good risk, you invest, but only if you are willing to take a chance on losing your money.
I've concluded that preordering from Cathe.com is an excellent investment, but I would never preorder anyone's DVDs if I couldn't take the risk of losing my money. In fact I only started preordering recently, when I was sure I could handle the loss of a preorder, because you never know what real life will do to a business plan.
Cathe.com does "want people to preorder" but does not force us to do it. Instead, the company gives us an excellent discount on preordered DVDs. If I decide that I don't like the DVDs after I get them, I know I will be able to sell or trade them and recoup my money.
For me, this risk is acceptable because I have investigated the company and am willing to take the risk. But if you don't feel the risk is acceptable, then you definitely should not preorder.