Received an email about this a few hours ago.
Redeemed at Melbourne Central store, just said I was after the $5 Chicken Chia burrito, didn't have to produce a membership card or show the email so it seems its an open offer to all.
I prefer Guzman Y Gomez but for half the price it's a tasty and filling meal made fresh. Yum!
Locations (different states on the left side): http://www.salsas.com.au/locations-VIC