User blog comment:Blackendedsoul/Smoker's Bravery/@comment-3242083-20120319194521/@comment-3425840-20120320122524

How do you know Smoker could hold his own against Shichibukais back then? They never actually fought at that time.

As for Luffy's part, at least part of is was public knowledge so they (the higher ups) could put a finger on it without raising question.