I just found this story last night. (Cory also has a post) Good for them. It appears the truckers wanted to go through the reservation to avoid weigh stations and fees;
Five Lakotas on Pine Ridge Indian land in South Dakota were arrested Monday after attempting to block two tarsands pipeline trucks from entering their land. According to the Lakota activist the six-hour standoff started when the trucks refused to turn around claiming they had “corporate rights that supersede any other law.â€
[youtube]http://www.youtube.com/watch?v=9OsHPnffvYI&feature=player_embedded[/youtube]