SDC adds a cardinality restriction to Questionanire.subjectType of 1..1 (compared to 0..* in regular Questionnaire). I see a couple of problems with this:

1) The requirement that a subjectType be present means that many Questionnaires might not be usable in SDC apps, e.g. the LOINC questionnaires returned by their FHIR API, which do not specify subjectType.

2) The requirement that only one subjectType be present eliminates the possibility of the Questionnaire being used for multiple types of subjects in possibly different settings. For example, the Hunger Vital Signs form could conceivably be used in a clinical setting with subjectType "Patient" or a non-clinical setting with subjectType "Person".

I propose relaxing subjectType back to 0..* as it is in the regular Questionnaire.