We have gotten to the point that we think we are safe, when the SDB's are closed, and only we have the "other key". Not so. You will go with the Crook and open the box, while his/her accomplice waits, with your family! My thought is not let anyone know you have anything of value, to start with. Much less a nice collection.
I have never had a SDB, because I have never had anything of value to put in one!
Looking at it from the crooks point, The last thing I would want to find in a place where I intended taking that which was not mine, would be a dog! people don't like 'barking dogs", and they look to see why it is making a fuss. Everyone knows what his neighbors look like, even if they are not known to each other personally. So the dog barks, and they look, then call the police. Or the crook(s) will be hauled off, (or the barking dog). Usually the crooks. My next door neighbors have no inkling that I collect coins, and they feel at home while visiting our house. Nothing looks "out of keeping with the rest of the furnishings, so no attention drawn to a big safe sitting is sight in one of the rooms. no safe here. Nothing worth a second look. Those of you who know about the others coin collections are of the same thought. Little know, less attraction.
There was a time when one never had to lock the doors. A their could care less about locks. The honest person doesn't worry about a lock, and the thief could care less. The only time I worry, or wonder, when I leave home, is when there are "Newly acquired family members", who learn of the collection, later. They might comment to friends, (who we don't know, and maybe "let the cat out of the bag". In my case, they intruder has to break in, making a lot of noise, then that is only the first door, or window. there are others, and finally the dog. Some are taught to attack an intruder, without making noise. Then you have to "break out, again, making a lot of noise. You can't go back the way you came in, because the neighbors are all watching, and wondering what is all the noise? By then the Cops are there, and the crooks are caught, red-handed. Bottom line: The more you "show", the more the crooks know! If you can't keep a secret, just hand then the key. Less damage that way. And, you lose, either way.
Dick