I've been making missions since Operation Flashpoint and I was curious as to what the Guarded By Triggers and Guard Waypoints actually are used for.

In short, they are the simplest way to put down reinforcements of objectives. This link (http://community.bistudio.com/wiki/Waypoint:Guard) has everything you need to know about Guarded Waypoints and Triggers.

So if you've been using my Reinforcements script, make sure you read up about these, as you may not need an scripting to achieve what you want.