This answers my question about Jay Leno's self-written monologue violating union rules.
"The Writers Guild of America had scolded the "Tonight Show" host earlier Thursday for penning and delivering punch lines in his first monologue in two months, aired on NBC the night before.
NBC quickly fired back, arguing Leno, a guild member, was right and the guild was wrong.
"The WGA agreement permits Jay Leno to write his own monologue for `The Tonight Show,'" NBC said in a statement. "The WGA is not permitted to implement rules that conflict with the terms of the collective bargaining agreement between the studios and the WGA."