Dodgy Postal Votes

In her Independent article "How dodgy postal votes may decide our next government", Mary Ann Sieghart warns of the abuse of the postal voting system. She points out that because postal votes are not secret in the same way as they would be if you entered a polling booth, voters are open to coercion (however mild) from others, who may be family members. Furthermore she claims there is an imported cultural element to this abuse of the system:
"the Biraderi tradition of clan politics that has been imported into many communities from the Asian sub-continent lent itself to the delivery of block votes to a party. Sometimes these postal ballot papers are taken to "voting factories", to be filled in by party activists."
This type of problem could also affect Interactive Democracy. How could we counter it?
The system could identify IP addresses where many votes are cast, enabling authorities to keep an eye out for vote factories.
The web site could have a call for help button and could include a page about the legality of coercive voting. Perhaps the police could even use the computers microphone and camera to gather evidence of coercive behaviour once the help button was pressed.
The site would include user defined user names and passwords to keep each citizen's account secret.
But despite all the technological solutions this seems to me to be a cultural issue that requires individuals to stand up for their own rights for independent votes.