I've never kidnapped anyone, but I imagine these are some benefits from doing so.
  1. You don't have to pay anyone, unlike adoption
  2. If they're young enough, they won't remember, like adoption
  3. There's a good chance you'll get on the news finally
  4. You'll be able to sit down and have a nice chat with a negotiator
  5. You can improve your pawnshop dealing skills
  6. You can observe the psychological effects of being a hostage without actually being a hostage
  7. You could meet Liam Neeson in person!