You can’t (except that it will mount to the mount point specified in the fstab, to /run/media/$USER/xxx/ otherwise).
Dolphin/KDE uses udisks2 (and GNOME e.g. too) for this.
Whether a password is required or not is governed by polkit.
On a default setup/installation, logged in users are allowed to mount removable/external disks/media without having to enter a password, and I would argue that this is what most users expect.
If you do want to require a password, change the security level to “secure”, but this will have other effects too (e.g. you’ll have to enter the root password to install updates via the desktop update applet).
You can use YaST->Security and Users->Security Center and System Hardening for that (Miscellaneous Settings->File Permissions), or edit /etc/sysconfig/security with a text editor (set PERMISSION_SECURITY to “secure local” and run “/sbin/set_polkit_default_privs” afterwards to actually apply the changes).
Or, you can just override the settings for this (or other) particular action(s) in /etc/polkit-default-privs.local.
Add this line with a text editor for requiring the root password:
You can change “auth_admin” to “auth_self” to request the user password, or to “no” to forbid mounting completely if you wanted to.
Again you have to run /sbin/set_polkit_default_privs afterwards to apply the change.
This is no different to 13.1 btw…
BTW, am finding 42.2 a bit of a disappointment in terms of look, feel and touch - clunky compared to 13.1 - and a bit prone to crashes (kde/plasma). Wonder if anyone else feels the same.
Well, it runs perfectly stable here.
If Plasma crashes, it’s most likely due to the graphics driver though.
The look and feel is configurable. If you don’t like the default one, just change it.
It can be made to look quite similar to 4.x (as used in 13.1). You may have to install some oxygen* packages manually though (oxygen was the default look and feel in “KDE4”).