The XOOPS Cube Legacy 2.1 package had to simulate actions of
beginners, because many users had forgotten removing the
install directory and their servers had been used to attack
other sites by anonymous attackers.
We had another idea that locks the install directory
automatically with password. But, that was too difficult to
handle for not only users but developers. So, we had chosen
to make it strict installation step.
However, here is the work around. It's possible to prevent
the blocker by the following site preload:
PreventInstallBlocker.class.php:
<?php
define("LEGACY_INSTALLERCHECKER_ACTIVE", false);
?>
If a user puts this preload file to his preload directory,
it's possible to continue the installation process without
blocking. And, he will see the read alert in the control
panel as well as XOOPS2.
gigamaster 
Actually end of installation don't provide a
possibility to the user to continue using XOOPS Cube
through the installer.
The user browser experience is broken!
The user is not free to choose. Because there is no
choice given.
And it requires extra software and extra steps to
achieve installation and start to use XOOPS Cube.
Maybe provide here a function to rename or remove/delete
install folder from the interface.
If it is not possible, remove "block process" but keep
an "Alert Message" !
So, users are informed about the risk and free to act.