Hi Terry. Once an ArcGIS Online Feature Service is made public, you cannot prevent anonymous users from editing the information, unless you block editing on the feature service for everyone.
Tentatively, in the December update of ArcGIS Online a new feature will be implemented allowing you to create read-only views of Feature Services. This would be useful when you want to keep the editable feature service private, and the data available for everyone to see... Coincidentally the Survey123 team will be the first to implement this feature so I guess you just got lucky We are doing our best to get this feature into Survey123 before the end of the year, but if we miss the December release we want to make it available in early 2017. Realistically, our main goal with Survey123 is first to resolve the problem where a group of people needs to capture data, and a different group (without edit privileges) needs to view the results of the survey (Data and Analyze tabs in survey123.arcgis.com). In any event, the essential foundation to solve the problem you are facing will be ready.
Here are the basics of how I would see this working for you:
- First you will publish a survey as usual (must be a NEW survey)
- Second, you will go to the Collaborate tab in survey123.arcgis.com as usual.
- This time you will have a chance to share with Groups that will submit data (as usual) and also have a new option to additionally share with Groups that will be able to see the Data and Analyze tabs. If you choose to share with these Groups a new Feature Service View will be created under your My Contents, which you will be able to manually share with everyone. This Public Feature Service view will have editing capabilities disabled. The trick here is that the Feature Service used by the Survey123 app will be secured, always forcing users to login.
It is still a bit early to say exactly how things will work, but as you can see we are trying to resolve the problem. In the meantime, I suggest you ask people using the Survey123 app not to log out of it, so the editor tracking info is always sent to the feature service (even if shared publicly). You cannot enforce it, but you can always ask...