Quoted from westofrome:
One thing I'm surprised we haven't seen are motorized outlane posts. These could be used to:
1) Allow the operator to adjust difficulty much more easily - or even have the game adjust based on auto-percentaging.
2) Allow in-game variation through:
a) modes in which they are more or less open or closed, or where the posts oscillate
b) earning of closed posts through awards
3) Allow unique competitive scenarios where:
a) Handicapped positions based on player strength in a multi-player game
b) Ensure remote games connected online have equal post settings
PopBumperPete mentions these can be gates.
You can also get the same thing with a kickback.