A Cinema 4D C.O.F.F.E.E. script that adds a compositing tag to a selected object with "Seen by Camera" off by default.

addExpresso.CSC

main(doc,op)
{
  // Insert a compositing tag on the selected object
  if (!op)
    return NULL;

  var compositingTag = AllocTag(Tcompositing);
  compositingTag#COMPOSITINGTAG_SEENBYCAMERA = 0;
  op->InsertTag(compositingTag);
}