Follow up: How to write a Linux virus

First, I don't have icons on my desktop:
KDE requires you to authorise them & defaults to 'no'.
I always download to a dir ~/hold/ & open from there
with the app of choice, eg Xpdf Most or Gvim. The proper way to use
an environment with multiple desktops is to have different apps on them,
which take up the whole screen (or nearly), obscuring any icons:
app launchers belong on the panel or you can use something like Apwal
(which has long been my preference).

However, many people prefer the Windows way of having document launchers
spread out all over their desktop, minimising them to the taskbar
& re-maximising them again all the time (I find that confusing),
so KDE etc need to protect against the ploy described by Foobar.

Surely, the simple way to do this is to limit the apps which are allowed
to be started via desktop icons. There would be a default list
in the KDE Control Centre -- eg Kwrite Kpdf Konqueror Kview Koffice -- ,
which the user could add to or alter subject to a Big Awful Warning !
eg I might alter the last two to Feh & OpenOffice & you could also add
scripts -- Bash Python etc -- , if you knew enough to want to.

The kind of Joe User who is ready to drop an unknown file on his desktop
would be unlikely ever to venture into the Control Centre
& if he ignored the Big Warning, there's nothing more anyone can do.
On multi-user systems, the Sysadmin could set it up to prevent users
from altering the default list of apps or accessing the KCC at all.

Joe User could drop any genuine picture PDF etc onto his desktop
& when he clicked it would be opened by Kview Kpdf etc without hindrance.
If the file contained a (malicious) Python script, it would not be run,
as Python would not be among the default list of useable apps.

Isn't this the proper UNIX approach to solving the problem ?
Why haven't the KDE devs -- whom I much admire -- dealt with this yet ?