Usually, when you edit a requisition through the WebUI to add an interface to a node, the status field is going to be "1". With provision.pl (or REsT API), the status is not added and the default value is used instead (which is 1).
But, if this value is set to 3, the interface is going to be added as unmanaged when synchronizing the requisition which is a very useful feature, if you don't want to monitor a specific IP on a node, and you want to prevent execute the detectors on it.
Unfortunately, it is not possible to change the status through provision.pl (or REsT API) or the WebUI. Right now, you must edit the requisition XML directly from the pending directory to set the status and then synchronize the requisition.