Warning when creating a duplicate customer

At the moment it's possible to setup a new customer in Cloud POS when they already exist in the system. Where the same customer exists twice (or more) you should be able to merge their records so you have an accurate record of how much that customer has spent (without having to look at multiple records). At the very least it would be helpful to get a warning when you're creating a new customer that there's already a customer with that name in the system.