[EricH]

<R02-C> is a prohibition of anything intended to jam or interfere with opponents' sensors.

On second read, you sound like you were intending to try to ram them away from the line. That might work, except that I'd be more than willing to bet that they have a gyro and/or accelerometer to block that.

Regarding parking across their tunnel entrance with a wide-oriented robot: perfectly legal, easily possible if they're coming from the middle, and pretty easy to set up as an autonomous: orient parallel to the bump, and drive forward x distance. One blocked robot, coming right up. You can't get the 38" dimension through the tunnel without bumpers, let alone with.