USB flash drives automatically mounted (headless computer)

For the project SamplerBox, up to now I was using /dev/sda1 /media auto nofail 0 0 to have USB flash drives automatically mounted when inserted on the headless computer, see also Auto-mount and auto-remount with /etc/fstab. But this seems not very reliable, for example, when an USB flash drive is removed, and then re-inserted.

Is there an algorithm to decide if a symlink loops?

Unix systems usually just error out if they are confronted with a path that contains a symlink loop or just too many symlinks, because they have a limit to the number of symlinks they will traverse in one path lookup. But is there a way to actually decide if a given path resolves to something or contains a loop, even if it contains more links than a unix is willing to follow? Or is this a formally undecidable problem? And if it can be decided, can it be decided in a reasonable amount of time/memory (e.g. without having to visit all files on a filesystem)?