diff --git a/README.md b/README.md
index e354081..4095b73 100644
--- a/README.md
+++ b/README.md
@@ -38,11 +38,14 @@ Hook files from both directories are collectively parsed and executed in lexicog
 
 For ZFS snapshots intended to save your bacon the `00-*` naming convention is particularly critical. In `/usr/share/libalpm/hooks` you can see for example that when a kernel upgrade happens `60-mkinitcpio-remove.hook` is executed (deleting your existing `vmlinuz-*` kernel image for example at `/boot/vmlinuz-linux`). After that if you're using the `zfs-dkms` package which itself requires `dkms` which in turn installs `71-dkms-remove.hook` this hook removes your ZFS kernel module files. Both the `60-*` and optionally the `71-*` hook (for `zfs-dkms` users) run early due to their naming. If we don't create a snapshot before these hooks run we end up creating a snapshot without kernel image and without ZFS kernel module files. Our `00-*` hook files are executed early enough ensuring that a snapshot can safely return you to a working system.
 
-By default we identify the active system dataset by doing `findmnt / --noheadings --output source` which for example returns:
+We snapshot datasets that have the `space.quico:auto-snapshot` property set to `true`. By default we further limit datasets to only those that are currently mounted in your active operating system. We identify these by asking `findmnt` for a list of mounted file systems of `fstype=="zfs"` which for example returns:
 ```
+# findmnt --json --list --output 'fstype,source,target' | \
+  jq --raw-output '.[][] | select(.fstype=="zfs") | .source'
+
 zpool/root/archlinux
 ```
-If exactly one source returns that is the exact name of a ZFS dataset in an imported zpool we create a snapshot on it. If no source returns we silently exit. If more than one source returns we raise an error and halt the `pacman` transaction.
+If no dataset (or no _local_ dataset) has the property set correctly no snapshots are done. The script will print an info-level message about that on `pacman` transactions.
 
 We retain two different snapshot chains, one for `pacman` transactions that only affect what we are calling _trivial_ packages and a separate chain for _important_ packages. By default only the exact regular expression package name match `^(linux(-zen)?(-headers)?|systemd|zfs-(linux(-zen)?|dkms|utils))$` is considered important so in plain English any one of: