As far as I know, in REI3 every field in the form must have an equivalent property in a relation (except label, which is not an input field). It would be useful to have input control that does not represent a relationship property on the form. By capturing user data in these input controls (which are not a direct attribute of any relationship) we can decide what to do with that data. Currently every form in REI3 exposes one or more relationship attributes (or part of it), which sometimes makes it difficult to build a custom form without unnecessary relationships or attributes.
