One of my neighbors, not the one that's afraid if computers, had an experience recently that serves as a good example of why it's important to proofread things. Especially when you're talking about an order form.
They're getting ready for this big family thing, their youngest kid's first communion, and they're making a big deal about it, inviting friends and family to attend. So he goes online looking for communion invitations. After some time searching he finds what he wants and places his order. Prompt as you please, his order arrives about a week later when a truck drops off 137 cases of invitations!
Now I am not a hamster, I know he's inviting a lot of people but I doubt he's going to need quite that many! The moral of the story is make sure that you are clear about how many of something you're ordering. A lot of things can be ordered individually or in case lots and frequently the links for one are close to the other. If you don't pay attention to the checkout page you could be in for a surprise when UPS drops off a whole truckload of can openers!