Hi Kal_Lam,
The 5 minutes delay in synchronising the last submission before it is recognised that the voter has already voted is a huge constraint. Several votes can be submitted within this period.
2ndly, if the user refuse to refresh the page after the last data is recognised, then the updated information will not be uploaded unto his device and he
can vote again.
The safe-net i use for this is to set the “Last-Saved” feature for the name or ID field or some other fields and use it to prevent additional voting from the same device using the same credentials.
When this is combined with checking submitted data in the parent form, it provides better constraints for multiple submissions.
, though not perfect, since clearing caches can eliminate last-saved information.