Only users who have been invited to a project can access that project. Modelo users from other separate organizations from yours are not able to access your projects, models or any other data. If you share a link to either download a model file or grant an external user access to a particular model in Modelo for viewing purposes that link will not grant access to other models or data in your project, or to other projects.
As far as Modelo's internal policies on your data, all of your data is proprietary to your organization and Modelo will not access that data unless expressly requested in writing (via email or logged support chat) to do so for support or troubleshooting purposes. In the event the Modelo accesses your data for support purposes, your data will not be saved or shared externally.