They use a CSRF-token in the Video URL. So all downloader that somehow recover the URL from the Player will fail.
It only works if you play the video (without pausing or skipping) and capture all the data that enters the browser and recover the videofile from that.
I did it "by hand" with wireshark, but its a PITA and nothing easily done by non-technical experts.

If anybody knows a browser plugin that just does that, please tell me!

Quick outline to capture stream with wireshark:
(No I will not give further support. This method is DEFINITLY NOT FOOLPROOF! Even if its unlikely that you break something)

- Setup wireshark to sniff on your Internet device; start sniffing
- Play video in browser. Do not pause, skip or something else. wait until playing stops.
- stop sniffing in wireshark
- look for streamed data. select a single packet. click "follow tcp stream"
- select "response only"
- save response stream to file.
- crop tcp response header at the beginning of file with hexeditor.
- with a bit of luck you now have saved the video from bbtube.


If anybody knows an easier method please let us know!