The system is designed to avoid multiple entries even while anonymous mode is selected. In order to do this, it restricts the number of times that an IP address can take the activity. It also drops a cookie into a browser to avoid duplicate entries.
Participants are not restricted from taking the survey at this point, they are asked to login.
Often our clients would like to enter in participation - survey results, comments, etc - collected offline. The meetings & offline tab allows you to add multiple responses using the data entry button.
If you are at an event and would like to collect feedback and responses from one device, use a kiosk. Also located under the meetings & offline tab in your project.
If you would like to disable the IP restriction, you can turn it off under the settings gear on the navigation bar on the left.
How to let multiple people take a survey from the same device or IP address