Youtube api v2: paid-content param not filtering

Youtube api v2: paid-content param not filtering

This has been asked before but not answered afaik. The op of that question
was using js and I am using php, but the problem is the same: the
paid-content parameter does not seem filter out paid-content results.
http://gdata.youtube.com/feeds/api/videos?v=2&q=something&paid-content=false&hl=en&region=US
This "charts" one does seem to filter correctly:
http://gdata.youtube.com/feeds/api/charts/movies/most_recent?v=2&max-results=10&paid-content=false&hl=en&region=US
Perhaps it says somewhere in the api docs that paid-content is meant to
filter only the charts but not videos feeds, and I missed it?