How to present a feature in an iPhone app that is only available for certain locations

Question

I am working on an iPhone app for a real estate client. We want to use a "look up by MLS number" feature that, due to MLS restrictions, will only be return results from the region in which the client has MLS membership, which in this case is southern New England. The issue is described further at Accessing MLS info from an API.

How can I indicate this limitation to optimize the user experience for people both in and out of the region?

Some ideas:

1. Use "location services" in the app and only show the "look up by MLS number" feature if the user is within the region. The downside of this is that this alert would need to come up when someone is adding or editing a listing, and I'm not sure how to make it apparent why the app is asking to use location services at this point (since it would only be using it to determine whether or not to show the feature).
2. Always show the "look up by MLS number" feature and include a label that indicates that it only shows listings in the southern New England region. Also reiterate this in the results if someone enters a number that is outside of the region. The downside here is that people may ignore the label and get frustrated that their MLS numbers outside of the region are not returning results.

Answer 1

Option 1 seems to be more valid. For the rest of the people outside southern New England its just an annoying button that cant be clicked. And the explanation will also take up unnecessary screen space.

Perhaps you could show a splash screen the first time someone wants to edit a list with info about why you sometimes need to see where the user is located and why it is beneficial for him/her?

"The app wants to use your current location box" is one of the flaws of Ios apps because people want to know why they should allow it.