So I'm interpreting your title "BS Drains" are games that might be drainy in a more sneaky fashion as opposed to something like GB that's just designed to be evil.
Metallica's left outlane comes to mind. The right outlane/inlane area on skateball is goofy on some machines. The worst offender of all to me is future spa. Even with the gate open where you have 3 of the 4 lanes on the left that are safe, the ball still finds a way to find that one lane that'll drain you.