The background story is strange at least,

- Call the number listed on the website for verification, not the number on the card.

When it all checks out, then sure show the inspector around and give him a small introduction to Bitcoin, explain what you are doing.
Videocards are well within EMC emission specs, so i find it hard to believe you're causing a disturbance somewhere in your block far away.
But anyway you can nullify these emissions by placing your rigs in a Faraday cage built from fine chicken wire or conductive fabric.