Is there a way to have EVERYBODY on the watchlist by default?

It definitely saved as I tested it and it was working. Maybe I did something stupid afterwards. Il see if it sticks this time.

Seeing as you've introduced me to the wonderful world of triggers, I have decided to set up an overdue notification for the Techs. 

Iv set it up as 

WHEN > "Overdue / Not Overdue" is changed to "Overdue"

WHAT > "Add Comment" > "BLAH BLAH"

This doesnt seem to be applying the trigger when a job goes overdue (the expiry time becomes < current time)
Have I set it up right, and also would "ACTION > ADD COMMENT" also send out an email notification?

Another option is to set Escalations for your SLA(s) as opposed to using a Trigger (that's what I do). Of course this is specific to each Services service level agreement. Example, all my SLA(s) for a Service are configured to Escalate when due date / time is missed. This sends an Escalation notification to the Service Admin (me) and the Assignee. There also is a good amount of escalation options foe each SLA.

If those out of box configuration options don't work we can then look at Triggers. Unless you really need to add a comment. 

Just what I was after thanks