How's That Again?

We stayed in a hotel last night -- the Westin in Falls Church, Virginia. Great room, big, comfy bed -- and I got to wake up and take a swim in the morning. When I was down at the pool, I noticed something odd. There was a sign that read, in big letters: "Warning: Lifeguard is on duty." There was some smaller print under it, but I couldn't read it because my glasses weren't on.

But why on earth should I be warned that a lifeguard was on duty? Shouldn't I be warned if there was no lifeguard on duty, and I was taking my safety into my own hands?

Maybe the smaller print would have clarified things. Like:

WARNING:

LIFEGUARD IS ON DUTY

And she's a cannibal.

or

WARNING:
LIFEGUARD IS ON DUTY

But those who know fear burn at her touch.

or

WARNING:

LIFEGUARD IS ON DUTY

Elsewhere.

Any other possibilities?

Rob