Stopping customer opening two accounts

[TheOracle]

The problem is ... how could two different email address be monitered if the old reading does exist but the new one does not exist yet (or shows as different readings comparing on the first one entered) ?

Supposing you register an account for the first time. You fill out the form by including your email address. Then, you log out. Sometime later, you register another account with a new email address. How could these two email addresses be matched from the same user if these two readings shows differently ?

By IP Address, the customer could simply visit your site from another location and register another account (and so on).

As for the customer's name and customer's lastname. If the customer does register with the same readings, I suppose it would be possible to restrict these readings since identical matches could be found in the database.

Assuming you would consider to stop multiple registration by firstname and lastname (additionally to the already existing restrictions of emails), would you like to add this your registration module ?

[distanceDemon]

Providing a unique identifier for a customer seems to be the issue here. This would have to be email address-firstname+last name-address, I think. I guess there is a law of diminishing returns at work here - more queries needed => slower site=>customers more likely to leave site and not complete signup.

To go slightly off topic for a moment, I have thought about the "why do we need them to sign up" question at length and do believe that that the speed of operation of check out is a critical point in the process. I would like to see an option for the user's details to be used to create an account after they have entered delivery details and payment method rather than the insistence on account creation. If no is selected, then the user should be informed that their details would be held for a period of ??? (configurable to the shop's returns policy period) to allow for queries or returns.

In my own case, I have decided to resolve the duplicate accounts problem by removing the 10% discount for new accounts. I have to acknowledge that we all have problems remembering the many many login/password combinations that we have and that people may well be genuine in their need to create a new account.
W