[rt-users] check for available recipients on reply

[inbel1 at telenet.be]

I'm wondering about this one ...

Our internal staff uses comments to put information in tickets for co-workers that can't be viewed by customers.
Customer information is shared via correspondence.

Last week, a staff member deleted (accidentaly) the requestor of a ticket.  There were no other cc's or admin cc's.
When the staff member clicked on Reply, RT did not sent a outgoing mail, but the message was flagged as Correspondence.

So I would like to make a check that returns an error to the user when he/she tries to reply on a ticket with no watchers.
Should I try to do it with a scrip or should I adapt the Email.pm?