I don't get it

According to CNN, the pizza deliveryman slash bank robber with bomb locked to his neck was in on the plot. He wasn't a victim, but rather a co-conspirator.

OK, so why exactly was the bomb live? I mean, a realistic-looking fake bomb would suffice as "explanation" for why you did it. So why did he let them lock a live bomb on him? Romance writers have a saying about their fictional characters. "TSTL" - "Too Stupid To Live." Is this a real case of TSTL or am I missing something here?