Nobody cares if someone innocent is busted for saying "Yeah, let's bomb a bridge!" What people are afraid of is that the FBI is the only thing pushing real terrorism forward. That but for the FBI, it would ALL be just talk. That's pretty dangerous if you ask me.
(To my follow-up comment, I forgot to add: what if the person who precipitates the terrorist plot and manoeuvers into being the final link in the chain simply CAN'T be that link. Maybe they get EXTREMELY ill, maybe they die, maybe someone else convinces the rest of the organization to let THEM do it, what if all the pieces are laid and then the informant is simply replaced by someone who doesn't know enough not to set the thing off at the end...)
The bombs are duds. Meaning that even if they attempt to set them of, nothing will happen.
And, presumably the FBI is keeping so well tap on them that if they somehow got acces to real explosives (which can't be that hard, considering Tanerite is legal, as is fertilizer if purchased in small enough quantities) they would be arrested earlier.
They may be 'duds', but there are plenty of instances of the FBI providing actual explosives even if the 'detonator' is not going to work large quantities of high explosives in and of themselves are dangerous.
Nobody cares if someone innocent is busted for saying "Yeah, let's bomb a bridge!" What people are afraid of is that the FBI is the only thing pushing real terrorism forward. That but for the FBI, it would ALL be just talk. That's pretty dangerous if you ask me.
(To my follow-up comment, I forgot to add: what if the person who precipitates the terrorist plot and manoeuvers into being the final link in the chain simply CAN'T be that link. Maybe they get EXTREMELY ill, maybe they die, maybe someone else convinces the rest of the organization to let THEM do it, what if all the pieces are laid and then the informant is simply replaced by someone who doesn't know enough not to set the thing off at the end...)