For most of the installations of LinuxMint the users' UIDs do not present a problem when managed via users-admin tool.
The tool is sleak and well matched with the LinuxMint look-and-feel.
The problem starts when LinuxMint is to be installed in existing and more demanding environment. In such case the 16bit integer limit on UID makes that tool unusable and a command line adduser has to be used.
I am sure there are other limitations but this one makes really no sense at all, as Linux itself (and UIDs as well) are at least 32bit for a long time.
Since I am not sure who supports LinuxMint version of users-admin tool (which seems to be very well integrated), I post it here and I hope that this post will get to the developers.