Copy Fields to Hidden Description

Hello,

Is it possible to use a script to copy Resource fields to the Description field if I uncheck "Requester can Set" Description?

I want to prevent users from entering information into the Description field and use my custom Resource fields instead; then I want to copy the Resource field values to the Description field. (This makes viewing the ticket more convenient for the technician, so they don't have to scroll to the bottom of the ticket to view the Resource field information.)

My attached script works as long as the Requester can set the Description. But when I uncheck it, the script does not work and the Description is left blank.