Please go read my post #80 and get back to us on that.
These were effective advertisements because they were designed to play on what people are looking for in a bomb. That may be stupid, but it is what it is.
You go placing these things on vital infrastructure all over town, somebody is going to notice and react. Certainly you are not contending that this reaction was not entirely forseeable, if not inevitable.
They were designed to elicit the reaction they got. Free advertising for Turner at the cost of paralyzing a city for a day. Lots of buzz for Turner at the cost of planting in the mind of people that unauthorized devices strapped to bridge supports is no big deal.
But no blood, no foul... right?
Your scenario is just ABSURD! No one in their right mind would do what you propose, knowing the trouble they would be in.