Knocking on the table in place of clapping at the end of a debate

Some months ago, I watched Coppola's "Dracula", and there was a scene in which, at end of Van Helsing's lesson, people knocked on the table, and I couldn't understand why.

I've just watched "Thumbsucker", and the guys knock on the table at the end of a debate.

This time, I made my homeworks and, making a little search, for example here:
http://www.mrshea.com/misc/knocking_applause.htm
it says this is used in place of clapping, but it's a tradition from Germany and perhaps near countries.

Just wondering if this tradition was actually exported and used eleswhere.
I also mean: the guys in the film were told to use knocking instead of clapping, because...?



I'm Winston Wolf. I solve problems.

...And no dream is ever... just a dream...