They are losing grip at the turn something they don't want to do. There is a big difference between that and intentionally breaking it loose and keeping it in control. Don't get me wrong, I'm not bashing or being sarcastic here, but that is not drifting. Look at this video, this is drifting, I have yet to see a 2wd RC drift controllably like this - but if you come by one post it so we can see:
http://www.youtube.com/v/0TraYbBVRH4