As an ex-security consultant, I ran into a lot of the Simplex locks at clients sites. Generally, they were "adequate" but definitely not superior.
There is, posted on the internet, instructions to figure out an unknown combination for these locks, by manipulating the buttons and pressing others. While this is easily available, I have not yet found anyone who could perform the job in a reasonable amount of time. Usually, there were other ways into the area, which worked faster than figuring out the combination, with the internet instructions.
This is not a problem for an individual using one of these locks at home, BUT, the most common compromise to these locks was that in about 60% of the places where we found them in use, we found the actual combination written on the wall, or under a picture, or on a nearby fire extinguisher tag, nearby. ( we found this even in government areas ) Someone wanting to get in, need only scour the walls, etc., in the vicinity of the Simplex lock, and often he could find the combination written down, someplace.
As far as my own garage, in my neighborhood, sure, I'd use them, but they aren't for use in high risk/high vulnerability locations.
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