Except they DO sign leases specifically prohibiting firearms.
Here is a 10 year lease, signed in December for the Children's Museum. See Section 7.3
7.3 Firearms . Museum agrees that it shall not permit any person to enter or remain within the Premises while in possession of a firearm, including a concealed firearm, whether or not the person carrying said firearm is licensed or permitted to carry a firearm or concealed firearm. Firearms are defined for purposes of this Lease as any object or device which is designed to explosively discharge any object or force including any electrical charge, which has the capacity of causing injury or inflicting pain and specifically includes, guns, pistols, rifles (whether any of the same are powered by gunpowder, compressed air or gas), tasers, bow and arrow and cross-bow. Museum shall, upon discovery that such a person is within the premises, ask that person to leave, and shall promptly summon law enforcement if the person does not comply with that request.
But, on the flip.
Here is a 10 year lease, from 2006 (still in effect), for the VERA project.
Search the lease and there is contradictory information. In one section, I-B:3, it specifically states:
Then, the next section states:Possess a firearm on the campus, except that such restrictionshall not apply to any pistol in the possession of a person licensedunder RCW 9.41.070 or exempt from the licensing requirement by RCW9.41.060.
Weapons are defined early on in the lease:C. Contraband in Seattle Center facilitiesThe following items are prohibited on the Seattle Center campus:illegal drugs, weapons, explosive devices, spray paint, lasers.
18. "Weapon" means any firearm or any instrument designed orintended to propel a missile of any kind, or any knife having a bladeof three inches or more, or any straight-edge razor, spring stick,metal knuckles, blackjack, bat, club or other bludgeon-typeinstrument, or any flailing instrument consisting of two or morerigid parts connected in such a manner as to allow them to swingfreely, such as nun chahkas, nunchakus or shurikens, or chains, orwhips, or stars, or darts, or stun gun, or taser, or any disc havingat least two points or pointed blades which is designed to be thrownor propelled.19. "Weapon violation" means possession or use of a weapon inviolation of Chapter 9.41 of the Revised Code of Washington, Chapter12A.14 of the Seattle Municipal Code or other applicable statute or ordinance.