Re: (context post by theymos)

After investigating some more, I found that nLockTime requires in-memory transaction replacement to be re-activated for it to be useful.

if (mapNextTx.count(outpoint))
        {
            // Disable replacement feature for now
            return false;

            // Allow replacing with a newer version of the same transaction
            if (i != 0)
                return false;
            ptxOld = mapNextTx[outpoint].ptx;
            if (!IsNewerThan(*ptxOld))
                return false;
            for (int i = 0; i < vin.size(); i++)
            {
                COutPoint outpoint = vin[i].prevout;
                if (!mapNextTx.count(outpoint) || mapNextTx[outpoint].ptx != ptxOld)
                    return false;
            }
            break;