[EricH]

The REAL game-changers are the ones that led to a rule change the next year.

1997: Team Hammond intentionally detaches a mechanism that scores lots of points. This device and anything like it is banned the next year.

1993(?): The robots that intentionally tip other robots are banned by 1994.

2002: FRC71 (the aforementioned Team Hammond, or the Beatty Beast) uses a walking drivetrain with filecard traction. While they weren't the only team with metal on carpet, they are probably the most famous. Metal on carpet was banned the next year due to the damage.

2005: Two of the three world champions had defensive wedges, but that isn't what got wedges banned starting in 2006. The one and only eliminations tie is, caused by each alliance tipping a member of the opposing alliance--why yes, wedges were involved. Bumpers were encouraged starting in 2006, and wedges were banned.

And then there was 469 in 2010.