I don't know about that... effective I guess but aren't you popping all the seeds under the skin?
Lots of juice on the plate. I score mine, then pull in half (in a bowl of water) then de-seed all underwater. No mess and the seeds sink to the bottom, pith floats.
Will have to try the 'spanking' method just for the fun of it...as long as I don't have to wear my hair like that smileys/smile.gif