In Our case The Store Config option Require Customer For Sale, will be helpful if add a field that allow to asígn a default customer.
Kelia, We have those kinds of situations, too. We started by using a dummy customer with a name similar to "guest". But I noticed an interesting report in PHP POS - in Customer Reports, there's one for sales by zip code. That in itself isn't very interesting, but there are a bunch of apps that will plot the data on a map for you, and some for no charge. Since we've been asking for zip code as an alternative to their real name (and entering it as zip code as well, of course), we've had only one person refuse to give it to us. It's entirely non-threatening in terms of privacy, and provides us with some interesting data.
I created a customer called "Guest" and use that whenever the customers do not want to share their info
It seems that if you use default customers, you wouldn't want to "require customer", but I might be missing something.
If you don't "require customer" then in most cases the employees will forget to ask the customer for their phone number. So the "require customer" setting reminds the clerk to ask for it.
If the customer does not want to be part of our "rewards program" we just us a guest account, that we have created with a phone number of "111" so it's easy for the clerk to choose the guest account.