Sarcasm

We were watching the Super Bowl, and a television commercial for a bank came on.
I read the fine print:
SUBSTANTIAL PENALTY FOR EARLY WITHDRAWAL.
I made a joke: “What do they do, cut your head off?”
Everybody in the room went silent.
And the red alarm dot on the television began to flash.
“Oh, shit… the sarcasm detector,” said the host. “They heard him.”
“They? Who?” I asked.
The screen went black, and outside… the sound of an approaching helicopter.
Oh great. The Sarcasm Police. Just what I need.
The red dot on top of the television flashed brighter.