Lately, I've been asking those I trade with if their tanks are coral pest free. If I sense any inkling of doubt, I do an iodine dip.
Basically, I start with a very dark soup of Seachem's Coral Dip for about 10-15 minutes. Just enough so I can barely see the coral in the container. If there are any pests, they will more than likely have fallen off the coral after getting stunned by the dip. I'll also use a toothbrush to remove any debris, egg mass, etc., from the coral and base. If I find anything on the coral in the container, I then proceed accordingly to the next dip (i.e. Interceptor for red bugs, etc.).
If I find nothing, I slowly start replacing the dip with new water, so it becomes clearer. I then inspect every millimeter of the piece with a flashlight and tweezers (sometimes a magnifying glass if needed). If I still find nothing, it goes straight to the display.
So far, I've never come across anything from those that have given me a very confident guarantee (knock on wood). If I did, I'd rip them a new one all over the boards.
HTH :wink: