Create a playlist in your youtube account.
Download the playlist page and save it as html.
Install youtube-dl: sudo apt-get install youtube-dl
Start youtube_pl2vids.py script with the path of the playlist.html.
For example: python youtube_pl2m3u.py playlist.html vidsdirectory
Your videos will be downloaded and placed in the ‘vidsdirectory’

The script will sleep for some random seconds between downloading the vids to simulate human interaction.