Well, schism is defined by whether or not one is able to receive the Eucharist. You are correct in saying that some disciplinary measures would not cause schism. When the Eucharist is involved, however, schism is always a possibility hanging at the door.
Dear skellmeyer,
"When the Eucharist is involved, however, schism is always a possibility hanging at the door."
I don't disagree, but that two bishops might disagree over whether an individual ought to be excommunicated or not is not of itself schism. It's something, if there is a direct conflict, to bring to Rome.
Now, once the Holy See makes a final determination, to directly refuse to obey, acknowledging one's disobedience, would likely be schismatic.
sitetest