Not too long ago, virtually every e-commerce site required you to register before making a purchase. Then, someone had the smart idea to allow “guest” transactions, so you could buy products or complete other tasks without fussing with the registration process. From what I understand, offering the guest option leads to happier customers and more sales.

Ok, so letting people buy without forced registration is a good idea. But what if an existing customer chooses the guest option, even though your records show they already have an account? Should you let them continue as a guest, or force them to remember their account information so they can act like a registered user?

I ran into this exact scenario with a travel site over the weekend. I haven’t used my account there in years, so I tried to select the guest option. The site refused to let me purchase the trip I had selected, insisting that I sign in to my account. I eventually retrieved my account info and completed the transaction. However, I’m sure that some percentage of people would have given up before that point.

The moral here is this: if you provide a guest checkout option, make sure anyone can use it. New customers, existing customers who forgot their password, existing customers who are in a rush — whatever. After all, a sale is a sale. If you put up a roadblock that keeps people from completing their transactions, it’s bound to hurt the bottom line.