Several teams of subcontracted YouTube workers went on strike on Friday, to protest a return-to-office policy that they say is an attempt by YouTube’s parent company, Alphabet, to bust their union. The case could have implications that reverberate across Silicon Valley. Around 40 workers in total, who are directly employed by Alphabet’s outsourcing partner Cognizant, walked out on Friday in a formal strike against what they say are unfair labor practices.