On Wednesday, the Supreme Court casted a majority vote that a California regulation that allowed union organizers to recruit agricultural workers at the workplace was a violation of their employer’s constitutional rights. The regulation, that was a major achievement of the farmworkers’ movement led by Cesar Chaves in the 1970s, allowed union representatives to meet with workers on site an hour before and after work and during lunch breaks. In dissent, Justice Breyer says that “this regulation does not ‘appropriate’ anything; it regulates the employers’ right to exclude others.”
See "Supreme Court rules against union recruitment of farmworkers on-site in California", Adam Liptak, The New York Times, June 24, 2021