I did some tests in the virtual machine. I installed 2 pclos edu : one in French that I updated, and one in English that I didn't update. Anyhow the update is not large, and does not contain any package that looks like it could interfere (but never know).
Then I booted the two, one after the other, and to be able to see if I could gain unprivileged access to other partitions, I added 2 other virtual machines to each as slave.
The result is so: at the beginning, I need to enter the root password in the prompted window, and later, I don't get the window that prompts me anymore, in any of the 2 versions : French updated and English not updated.
I did then a research in the PolicyKit docs, and this is what I found so far. Here, I can find the way to revoke authorisations:http://hal.freedesktop.org/docs/PolicyKit/polkit-auth.1.html
[--user user] --revoke action
Revoke all authorizations for an action. If the user is not specified the calling user is used. The authorization org.freedesktop.policykit.revoke is needed to revoke authorizations from other users.
Here I can get how to see in console the list of available actions:http://hal.freedesktop.org/docs/PolicyKit/polkit-action.1.html
the command "polkit-action" with no argument displays the list of available actions. I didn't get into all the details because I can't grab all this in one shot, and don't need it all now anyway.
Then, I looked a little in other docs too, reread the PolicyKit.conf doc:http://hal.freedesktop.org/docs/PolicyKit/PolicyKit.conf.5.html
and saw that another choice than thoses provided could be done with polkit-1, and not with PolicyKit.conf : I mean there is a value (option ? what is the correct name for it ?) as "admin_auth_one_shot", but this belongs to polkit-action. For now, appart from the command line I didn't find any clue on : "does the command line write it somewhere ?" and "in what file does that have to be written and what syntax ?".
Then another page brought me there:http://hal.freedesktop.org/docs/polkit/pklocalauthority.8.html
and now it looks to me like a big puzzle.
So I invoked in the root console:
polkit-auth user school --revoke org.freedesktop.hal.storage.mount-fixed
and the window prompting the root password was back !
What I want to get is a window prompting for the root password, and never providing the choice to keep or not an authorization : it would be better for the PCLinuxOS Education distribution that the authorization be canceled, after each time an internal partition is unmounted.
Do you have an idea how to do that the best way ?