I'm a little confused about your process of re-boarding in the ports . Every cruise we've been on we had to put our shopping bags, purses, etc., through the scanner. Did you not have to do this, or did they just ignore what came through? I'd be concerned, too.
Neither my girlfriend or I ever remember our stuff being scanned. One time I came through with 2 bottles another time 3 bottles. They never said a word I voluntarily gave them up at a table. I could have taken them to my room no questions asked. I thought security was very lax. Just an observation.
They do tell that the reserve the right to search any bag...