Tummy Tuck incision should NOT scab
A well-healing surgical wound does not scab, it heals with primarily with a very narrow area of visible wound. A scabbing wound implies there was superficial tissue death or a large raw surfaces which dried up. rather than soliciting opinions online, you should ask your surgeon what he would like you to do.
I routinely ask my patients to apply a thin layer of antibiotic ointment to keep such areas moist, which rapidly enhances healing, and acts as a mild bacterial barrier.