After playing for a while, I'm now under the impression that corkscrews are in fact placed completely randomly in the song. Unlike other people who seem to only encounter them at intense moments of songs, I may have actually encountered MORE of them in the least intense moments of songs (intro, outro), in addition to some others which seemed arbitrarily placed throughout tracks.
However, given that on any given track, the corkscrews will always be in the same place, there must be some sort of operation going on that determines their placement, but I'll be damned if I have a clue what it is.
Anyway, this was too long for a comment.