There is just so much nuance to the decision. If OP is URM and/or first gen, that score gets sent to Midd for sure. If they are from a strong HS, affluent, and caucasian, probably not sending it. Rigor, class standing will also play into the decision. Again, does the score strengthen the application, or not?
Most schools haven’t released acceptance rate data broken out by with and without test. For some of those that have, it appears that test submitters had higher acceptance rates than non-submitters. I would not have any fear that AOs assume something about a score that has not been submitted. Hope is not a good application strategy.