"Scaffolding Accident" joke

Steve, Bob, and Jeff were working on a very high scaffolding one day when suddenly, Steve falls off and is killed instantly. After the ambulance leaves with Steve's body, Bob and Jeff realize that one of them is going to have to tell Steve's wife.
Bob says he's good at this sort of sensitive stuff, so he volunteers to do the job. After two hours he returns, carrying a six-pack of beer.
"So did you tell her?" asks Jeff.
"Yep", replied Bob.
"Say, where did you get the six-pack?"
Bob informs Jeff. "She gave it to me!"
"What??" exclaims Jeff, "you just told her her husband died and she gave you a six-pack??"
"Sure," Bob says.
"Why?" asks Jeff.
"Well," Bob continues, "when she answered the door, I asked her,' are you Steve's widow?'
'Widow?', she said,' no, no, you're mistaken, I'm not a widow!'
So I said: "I'll bet you a six-pack you ARE!'"