None for a bomb. There is a safety difference, though, for dangerous goods that passengers inadvertently pack. I don't know that the safety difference is large enough to justify having an airline employee tagging the bag in terms of a cost benefit analysis. But the human interaction line of defense is gone and we are relying entirely on the TSA, and personally I'm not sure I trust them to be aware of what items are on the dangerous goods list (other than toner cartridges ) or to actually know how to screen for them.