Likes playlist is always empty

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Retrieve the ID's for the likes playlist
2. Retireve the items within the playlist ID returned on step 1
3. Behold an empty list

What is the expected output? What do you see instead?
The liked videos that are in the Likes playlist.

What version of the product are you using? On what operating system?
Firefox 35, Windows 7, and the Google APIs Explorer.

Please provide any additional information below.
I did this more exactly using the following:

https://www.googleapis.com/youtube/v3/channels?part=contentDetails&maxResults=50
&mine=true&key={YOUR_API_KEY}

This will spew out my channel, with playlist IDs for various builtin playlists, 
among which is the Likes. Also, "favorites" (what is that anyway? it doesn't 
show up anywhere on youtube.com). So I grabbed the ID for likes, and fed that 
into the next call:

https://www.googleapis.com/youtube/v3/playlistItems?part=contentDetails&id=UCBTU
t13bCVDMW5adk2ULZxw&key={YOUR_API_KEY}

This returns an empty list.

There are 163 videos in my Likes playlist. I logged in on the API explorer same 
as I do on youtube.com. So the empty Likes playlist seems like a bug to me.

Original issue reported on code.google.com by thany81 on 7 Feb 2015 at 9:56

[GoogleCodeExporter]

Forgot to mention: all the while being authorized via OAuth 2.0.

Original comment by thany81 on 7 Feb 2015 at 9:57

[GoogleCodeExporter]

And using playlistId instead of id doesn't help either.

https://www.googleapis.com/youtube/v3/playlistItems?part=contentDetails&playlist
Id=LLBTUt13bCVDMW5adk2ULZxw&key={YOUR_API_KEY}
Returns the same empty Likes playlist.

Original comment by thany81 on 7 Feb 2015 at 10:02