I've worked on quite a few distributed systems where you need to generate unique IDs and I can tell you that UUID is not a solution in quite a few of them becau

I've worked on quite a few distributed systems where you need to generate unique IDs and I can tell you that UUID is not a solution in quite a few of them because you actually need to understand what problem you are solving rather than taking the promises of others for granted or shrugging and gambling on thins sorting themselves out. In many cases you have two problems: network partitions and/or high ID assignment rates. So statements "if there ever was a conflict you'd have an API stating as much" is simply passing the buck to some piece of magic and actively not knowing what goes on. It is a bullshit statement. In my experience, this is the kind of problem where people tend to fail because they don't grasp that it is actually kinda hard. Especially if you have additional constraints (like the size of IDs). People tend to make all manner of assumptions and then not test those assumptions. The arguments are familiar though. I hear a re-run of them about every 2 years, when someone has a system in production and the thing starts to generate duplicate IDs. Although both code and notes are available on previous solutions within the company, people tend to ignore that and just plow ahead.