1) Video cameras are everywhere in Boston but prevented nothing.
2) The willingness of the Boston population to be penned up and have their travel restricted by "sheltering in place".
3) The well known "tough" gun control laws prevented citizens the opportunity of defending themselves if the situation had arisen. These same "tough" laws never prevented the bad guys from obtaining and using guns.
Also, in recent shootings, the MSM has screamed about the "assault weapons" used but in the case of obvious terrorism, they are silent on the type of weapons used except this (typically) idiotic Yahoo/Reuters story on that:
http://news.yahoo.com/boston-bombing-suspects-did-not-valid-handgun-licenses-234648018.html
Strictly speaking, the travel restriction was called off because after a day, people started ignoring it. Amusing that it was after people were officially allowed to walk around that the guy went into his yard and found the thug hiding in his boat.