IMHO it is clear that the behaviour of system/DE is not clearly documented for us mere users (or at least nobody of us could find it). Personaly I would love to know how it (should) function, because I then can update SDB:Basics of partitions, filesystems, mount points - openSUSE.
Some of my observations reading several threads here.
It is no longer HAL (or at least not HAL alone) that is involved, but DeviceKit.
The fact that the mounting (of CDs, DVDs, USB storage devices) is no longer done at connection, but following an action of the end-user may be a way to avoid the problem that HAL mounted for an arbritrary loged in user session (at least I could not find out which logic is used to make the choice between the loged in sessions). I did not test the new situation (still in the conversion phase to 11.2/KDE 4), but I it looks as if in the new situation the user that acts first, will get it mounted on his behalf (that means his uid is used as owner for the mountpoint and also for the contents if it is not a Lunix fs type).
To put it in other words:
In the old situation the device was mounted ready to be used by one of the loged in users without any further action needed by any user.
In the new situation the device is offered to all loged in users, and the user who acts first gets it (TO BE PROVEN!).
For those who always have one user loged in at the time (which is a case that may not be typical for a Unix/Linux like system, but in reality very often on laptop and even desktop systems) this might not be an improvement because of the exttra clicks needed.
For others it might be an improvment. Take the case of the loged in, but locked Father session (fathrte walked away), the also loged in and unlocked Mother session (also walked away), where the Daughter logs in and puts in a CD. In the old situation she saw nothing happening (because the pop-up was in one of the two other sessions). In the new situation she would get the notification and being the only one around would act and get it!
But in case of remote logins, this is still not ideal (be carefull with what you connect!).
Anybody who can point to more documentation?