A wave of unionization by service workers has swept through Silicon Valley in the last two years bringing wage increases, health benefits and job security to thousands of shuttle drivers, janitors, security guards and other hourly wage workers at big tech companies like Yahoo and Facebook. Now the union waters are lapping at the shores of Fremont where the giant Tesla plant employs over 5,000 automobile assembly line workers. Tom Herriman reports from Fremont. Photo: Tesla assembly line workers Richard Ortiz and Michael Sanchez.