Quoted from Isochronic_Frost:Since you mention mainly woodrails, possibly this was an operator trick to ensure that even if the tilt bob slips it simply gets harder instead of getting easier?
Back then games got played way more than anything nowadays. People probably shook the hell out of them to try and knock the tilt bob loose
I’ve been told that most operators preferred the tilt bob under the ring (pointy side up) so that if it fell off, the unit could still generate revenue. On route if it’s above and slides down, it’s out of action until the next coin collection for the most part.