Trying to catch save mode 5 and cancel the save does not work when deactivating a record

Repro:

Apply this script to the form and bind the save event (passing execution context)

function OnSave(execObj) {
alert(execObj.getEventArgs().getSaveMode());
if (execObj.getEventArgs().getSaveMode() === "5" || execObj.getEventArgs().getSaveMode() === 5) {
execObj.getEventArgs().preventDefault();
}
}

Save mode 5 is alerted but record still deactivates.

This worked in CRM 2011