In February 2005, Oosterman received worldwide attention when he was arrested at the start of the Auckland World Naked Bike Ride for refusing to put on underwear.

To protest this charge, he stripped off in front of the courthouse with three other activists wrapped in a banner reading "STOP indecent exposure to vehicle emissions".

On 22 March 2005, he and other protesters publicly complained about police brutality while passively resisting arrest for obstructing a footpath, following a peace demonstration that went inside an ANZ bank.

[5] In May 2006 he filed papers at the Auckland district court seeking NZ$50,000 in damages from the New Zealand police after being pepper sprayed at a January 2005 protest against an alleged genetic engineering experiment outside the Forest Research Institute in Rotorua.

[8] In July 2007, Oosterman, who runs a web hosting service for community groups, was forced to remove a Save Happy Valley Coalition spoof annual report of Solid Energy's environmental record, which included a logo of the state-owned enterprise, due to infringement of their copyright and trademark.