I only just started using LimeSurvey recently and so far it's been great. But there are still couple of points that I can't figure out.
I can see that when I use tokens + public registration LimeSurvey checks whether entered email has already been registered. This is good for preventing participants from completing the same survey multiple times.
But I need a way to restrict users from completing ALL surveys: any given user can only register and complete ONLY ONE survey! One survey per email!
So, if I register for Survey_1 and enter my email address, a token will be created for me. I can then complete this survey, get my results etc.
How can I make sure that I won't be able to participate in any other surveys on my server?
NOTE that I know there's an option to enable cookies that can restrict this, but this is NO GOOD as it's unreliable and I will be using LS within Iframes.
(posted this in 'Development' as I think that I might need to modify LimeSurvey to achieve the above)