When you place something in a safe it's usually important, so there is no chance you would leave it behind when you move out. Should not take too long to try all the combinations though.
Depends on the reason for moving out. Being deceased for example does make keeping material goods a bit more challenging.
I remember a program on TV, where they opened a few hundred old bank boxes hoping to find a treasure map. They of course did not find anything. Wouldn't you check many times if any box had anything of value before decommissioning them?
There is something very exiting and addicting with mystery boxes though...
Define "too long"? The post says it would take a specialized robot up to 3 days, with no guarantee of success.
90^5 / 3 / 24 / 3600 = approx. 23000 combinations/s
That rate seems much too high, for either a mechanical lock mechanism or an electronic keypad (which I guess would have some kind of lockout for brute forcing anyway).
No idea if that's a common problem with safes, but it's pretty clear that a safe would not have any outside maintenance access to fix a problem like that (other than drilling it open, which seems to be routine enough given the "yeah, we can make it usable again" offer)
2. It's a trap lock and was never designed to be operable in the first place.
Or as others said, the lock mechanism could be faulty or seized.
For example a standard Master dial lock has 40 hash marks but, IIRC, older ones had only about 12 valid positions. There was a trick you could use to find the third position, which would have left 144 combinations try except there were a few invalid combinations reducing to around 120. This is for a lock that a naive estimate would but at 40^3 or 64,000 combinations.
I once witnessed someone open a safe in a few hours. It is truly amazing to see these kind of proffesionals at work. How they approach this puzzle and the knowledge they can acquire by just feeling. Especially considering it took me a few tries to open the safe when I knew the combination.
But its not likely to tell the difference between 50-0-50 and 49-0-49. I suspect the "70% chance" for the robot to succeed is because it's going to try every 4th number or 5th number to hugely reduce the search space.
Trying every 5th number is just 8000 combinations!