I know what you mean....it's always a tricky one, the containers seem well made but then it's sods law that one of your animals will be over interested and do their level best to do a full investigation. Our pest control chap said that over the counter modern bait is no longer that strong and wouldn't knock out a cat or dog, if ingested. A worry, still.
We have used it to some effect but were able to place it in sectioned off areas, will tons of bricks on the bait boxes. We did better with fenn traps and better still shooting (rats have patterns, same routes used, usually at same times of the day) I popped smoke bombs in tunnels once but it was difficult to ensure that you had every hole covered.