Yes, each passenger will get 3 free bags. Its on the website.

http://www.united.com/CMS/en-US/trav...geChecked.aspx

"Certain customers are exempt from paying checked baggage service charges for one or more bags within specified size and weight limits. Customers traveling with MileagePlus Premier members or dependents traveling with active U.S. military personnel will have the same exemption as the customer whose status provides for the benefit, as long as they are traveling in the same reservation. This exemption will not apply to group reservations including 10 or more customers or when the flight is not operated by United or United Express®."