From memory...the c of g sensor reads the displacement of the nose gear oleo and through a clever magic box and calculation indicates to the flight crew the green band for the correct stab trim required.
If the a/c is loaded with the cargo pallets in the correct place, then there will be no anomalies.
However, if the pallets shift during the t/o roll or at rotation then the (I think) pilots will not get a warning.
Er...I think!
