It appears the Execute Script rule does not work to set/unset a Task when a Requester (who is not a Technician) creates a new Service Request or edits an existing Request. If the user is a Technician, it works fine. See below for the actual script included on this rule.
if($CS.getValue("RES_2104_QUS_1815")==="Laptop Required")
$CS.setTasks(["templateTask67511"]);
else
$CS.unSetTasks(["templateTask67511"]);