Such restrictions are valid only if they are not imposed in a discriminatory manner. For example, if employees are permitted by company policy to collect money for a wedding shower and baby gifts, to sell Avon-type products or Tupperware, or to engage in other solicitation during their working time, the employer will not be able to lawfully prohibit them from union soliciting during work time. Finally, remember that there are many more ways to commit unfair labor practices than just keeping union organizers off your private property.