> 
> This works: https://serverfault.com/questions/766506/automount-usb-drives-with-systemd <https://serverfault.com/questions/766506/automount-usb-drives-with-systemd>
>

This is great info. I have been dealing with udev programmatically recently
and I have learned a lot.
 
> Mostly. It doesn’t unmount on removal but that’s a small concern.
> 

As I was thinking about this, it occured to me that there is no clear way to
unmount a USB filesystem. And I mean, you cannot just anticipate the USB being
yanked out of the system... And, I saw what you wrote above, and I also read
the solution on the link, and could not help but think that you need a way of
doing a clean unmount.

The problem is that you can corrupt the filesystem on the USB drive/stick,
especially if there have been changes made (like deleting/writing files).
(It appears to be a "small concern" for you.)

So, this brings me to the higher level question on what you are trying to do.
Having people just putting in USB drives and expecting that they get full
functionality is a fallacy. But you can have people put in the USB drive, get
files _from_ it, and then unplug it. In this case you would force read-only
mounting, and I expect all would be fine. In the case that you want the data
on the USB drive to be able to be altered, you will need to have some way of
allowing the unmounting of the drive. The real problem is making users do it...