john: thank you, chris sprigman. >>> coming up, who owns a joke?do comedians deal with joke stealers? >>> and how do i deal with people who steal my brand? welcome to 20/20, i'm john stossel. >> i'm john stossel. nobody move! get on the floor! do something! oh i'm not a security guard, i'm a security monitor. i only notify people if there is a robbery. there's a robbery. why monitor a problem if you don't fix it? that's why lifelock does more than free credit monitoring to protect you from identity theft. we not only alert you to identity threats, if you have a problem, we'll spend up to a million dollars on lawyers and experts to fix it. lifelock. join starting at $9.99 a month. . john: have you heard this joke? why is six afraid of seven? because seven eight nine. get it? seven ate nine. does that make me a joke stealer? i think so, what does that mean for professional comedians, what do they do if someone steals their jokes. comedian doug stanhope says comedians work this out. i asked him about this because he's a libertarian. here's a sample of

john: thank you, chris sprigman. >>> coming up, who owns a joke?ans deal with joke stealers? >>> and how do i deal with people who steal my brand? welcome to 20/20, i'm john stossel. >> i'm john stossel. hey gabby, how you doing? how was the playdate and sleepover? dad, it was great! awesome! ok, i'm on my way. hey guys! what are you doin'? we're going swimming! we're going biking! yeah! i'll see you in a little bit, guys! i love you! hi babe! how was school today? hi dad, it was great! ok, honey, i'll be home soon. remember, you're never too far away from your kids, to be a dad. reach out and take a second to check in... because sometimes, the smallest moments can have the biggest impact on a child's life. . john: have you heard this joke? why is six afraid of seven? because seven eight nine. get it? seven ate nine. does that make me a joke stealer? i think so, what does that mean for professional comedians, what do they do if someone steals their jokes. comedian doug stanhope says comedians work this out. i asked him about this because he's a lib