I’d like an official response to send to my client.
Surveys created through SurveyGizmo are only accessible through a specific URL address that is generated as soon as you begin creating your project. These projects could be accessed through the default link (found under the ‘Share’ tab) or through an email campaign. This help document should help you differentiate between the two.
Unless an individual has access to this specific address, they will not be able to access your survey. So, in short, your survey will not be accessible through a simple Google search.