If someone is unsure they're able to make it (eg. needs to check their calendar), they can be tentatively rostered to the event.
The person being rostered will be reminded via email that they need to confirm their shift, as well as via SMS if they still haven't done-so a week away from the event (which they just need to reply via SMS to confirm they're able to attend).
Confirmation
The person rostered can confirm themselves via the home page.
Confirmation can also be done when viewing the event details;
