The meaning of the area code needs to be clarified when creating an entry for an unreviewed provider. In some markets, the exact same locations are covered by several area codes. What with phone number portability, the area code may have nothing to do with the provider's home base. If I search on one, I want to know that I will find the providers reviewed with the other. You can't necessarily count on a reviewer to know this. For instance in some large metropolitan areas several adjacent counties share the same three area codes. One of those is also used in a part of town where a lot of but not all providing takes place, but that county also uses two unique area codes.
the idea seems pretty straight forward to me. Just put the actual area code that is part of the phone number into the field. It doesn't really matter if multiple codes are present or if one code covers a large area.
If you don't have a phone number, with the area code, you don't need to put something real in. I think the suggestion in the guidelines is something like 555-555-5555.
I agree that portability has rendered area codes obsolete but it's still a useful search field. It can narrow down a search; it can help if you only have a partial exchange-number (EEE-NNNN). Basically, in the US we no longer have 7-digit phone numbers (+ 3 digit area code). We all have 10-digit phone numbers.
The meaning of the area code needs to be clarified when creating an entry for an unreviewed provider. In some markets, the exact same locations are covered by several area codes. What with phone number portability, the area code may have nothing to do with the provider's home base. If I search on one, I want to know that I will find the providers reviewed with the other. You can't necessarily count on a reviewer to know this. For instance in some large metropolitan areas several adjacent counties share the same three area codes. One of those is also used in a part of town where a lot of but not all providing takes place, but that county also uses two unique area codes.