You can actually set up a cronjob to do it.

crontab -e

add this:

@reboot ifconfig wlan0 down

You can actually set up a cronjob to do it.

sudo crontab -e

add this:

@reboot ifconfig wlan0 down

This cronjob will run every time the system boot.

This is not the most optimal solution, but it does what it is supposed to do. It is also very easy to remove :)