Customer Registration Email on Orders

[koryb1]

We have a very popular Rewards Program (Buy 10 Pairs of Select Shoes, Get 1 Pair Free) on our site. Customers don't often buy 10 pairs at once, so they earn their rewards over time.

But, as far as I can tell, it's not hard for customers to earn free rewards they're not entitled to:

1. Create a customer account with an email address and log in.
2. Purchase 10 pairs of shoes using a different email address.
3. Cancel/Return shoes. When we get cancellations or returns I look up their account using the email address they provided and manually deduct that # of pairs. But if I can't find the email address I have to assume they don't have an account.
4. Since 10 pairs were purchased, even though they were cancelled/returned, the customer could still claim a free pair.

The problem is that their registered email address is not shown with their order, and if they use a different email address with their order there is no way for us to know which account to adjust for cancellations/returns (I also search by last name and sometimes find the user in this manner but this doesn't always work either).

This issue commonly arises with orders paid by PayPal or Amazon. The customer places the order with a preferred email address, but when they checkout with Amazon/PayPal their accounts are set up with different email addresses.

So, is there a way to include the email address the customer is logged in with on the Order Confirmation template?

Thanks in advance,

Kory