Features of plugin.

1) Easy setup it can be done after few clicks.
2) No core file hacking.
3) Depends on virtue mart so virtue mart should be already install in site.
4) Well tested on all popular browser(IE,FF,Chrome,Safari etc)

Setup instruction of this plugin:

1) Install the plugin by extension manager.
2) Go to admin section of virtue mart.
3) Create new shopper field as a check-box(Field should be show in registration form).
4) Go to admin section of plugin,set the parameters.