Q: Why don’t eruvs use existing electrical lines?
A: Thou shalt not steal… it would be hot-wired.

Q: What’s an eruv checker’s favorite game show?
A: What’s My Line.

Q: What’s an eruv checker’s theme song?
A: Johnny Cash’s “I Walk The Line” … “I keep my eyes wide open all the time,
I keep the ends out for the tie that binds.”

Knock, knock.
Who’s there?
Eruv checker.
Eruv checker who?
Your backyard fence is broken. May we fix it for free?

Riddle: I often have doorways with neither doors nor walls. I am a boundary for people yet neither keep people in nor out. I belong to everyone, yet am owned by nobody. Although miles long, even one small flaw makes me entirely worthless. What am I?
A: An eruv.

Old eruv checkers don’t die, they just get strung out.

I’m not an eruv checker, I’m a pole-ster.