Do you wonder why a large inflatable rat stands nearby when a union is picketing?  In the building trades, “rat” is a term that unions sometimes use to refer to a non-union contractor.  A union typically sets up its inflatable rat (or, in some cases, a skunk) at its picket line at a site (e.g., an office building) where the non-union contractor is performing services.  The inflatable vermin is used to embarrass either the office building owner or tenants in the office building, and make them uncomfortable.  The hoped-for effect is to cause the office building owner or tenant to cease its business relationship with the non-union contractor in order to make the rat go away.  Whether the rat is protected “First Amendment Free Speech” or a violation of the National Labor Relations Act as an impermissible tool in a confrontational union campaign depends on the surrounding circumstances.