It seems pretty obvious to me that the reason the yellow badge worker's aren't given those benefits is to keep them separate from the rest of the work force for

It seems pretty obvious to me that the reason the yellow badge worker's aren't given those benefits is to keep them separate from the rest of the work force for security reasons (to keep them from talking about their work) They allow janitors and food service workers access to these perks, it seems kind of weirdly targeted if they are just doing it to save money. They're probably doing work that is so confidential that google doesn't want to give them the chance to socialize with other workers.