I think there is a misunderstanding of the concept of Party Interaction. This is used to log interactions with a Party in the e.g. sent an invite to an event, received a PoA form, notified of an Outage for a service, sent Invoice reminder, sent out invite to a questionaire etc. the list is almost endless. Each of these interaction usually contains the message or a link to the document sent/received.
So the invitation to a questionaire e.g. an SMS after Order is received to get the Customers experience woul be an Party Interaction. THe actual Q/A flow of the questionaire is not. However the result may be if it non anonomous i.e. we have a a Paty identifier and optionally a link to the result.