I’m a lifelong D.C. (and suburbs) resident, and heard this urban legend trick long ago. If you want to tour the Capitol, contact your Congressman or their staff. But you must first mentally change your residence to Hawaii, or Guam, or Samoa, or Alaska. We get lots of tourists from New York and Florida, but not many from Guam! With Congressional elections coming in November, congressional staff from small remote districts should be glad to meet their “constituents”!
I visited the Capitol as a kid, and don’t feel the urge to return. I can’t personally vouch for this trick, but let us know if you use it.