They are just following the law.Tigard pawn uses that to scam you out of money and have done so for years. They say we can't let any leave without a lock and have locks ready to sell to you. Also they charge you $2 to make a photocopy of your drivers license (it may be even higher now I don't know).
What does the Child Safety Lock Act of 2005 (CSLA) require of a licensee? | Bureau of Alcohol, Tobacco, Firearms and Explosives
When selling, delivering, or transferring a handgun to any person other than another licensee, any licensed importer, licensed manufacturer, or licensed dealer must provide a secure gun storage or safety device to that person for the handgun. [18 U.S.C. 922(z)]
www.atf.gov