We deployed the Damage Assessment Solution (Damage Assessment | ArcGIS Solutions for Emergency Management) and had our damage inspection team use the Survey123 Connect form to record damage to residential structures. One of the biggest problems we had with the data was a lack of good location data. Since the Location field was not required as a part of the default deployment, we relied heavily on the inspectors recording addresses accurately. (We have since made the Location field required, which will help a lot.) Unfortunately, with an open text field for addresses, the inspectors were able to enter invalid or partial addresses, which does no good for mapping purposes.
My idea is to set up a field in the Survey form that pulls valid address data from a web service that contains our address points. That way, when an inspector starts to type an address, it auto-completes with the correct format.
The only way to do this now would be to add each individual address to the choices worksheet in Survey123 Connect, but with 41,000+ addresses, this is highly impractical.
While this is a specific request for a specific solution, I can imagine many situations where you would want a field in a form to validate against your in-house GIS data.