I was amazed by one comment in this:

Science Daily on robots for defusing pipe bombs

Thousands of pipe bombs are made each year, and thousands of pipe bomb threats are called into local police and FBI authorities across the country.

I was near one in Pittsburgh in 1976 - it was in the storage tank of a gas station, with two other gas stations on the same intersection. The fourth corner was a multistorey block of sheltered housing for old Jewish people, and I was 50 yards away. If it it had gone off, I and the old Jews would have gone up in the biggest fireball America had seen since Pearl Harbor. It was found and defused; it was part of an extortion campaign and a few other gas stations around the city were targeted.

I thought at the time that that was a wildly aberrant event. But it seems it's absolutely routine, something virtually every urban police force would expect to deal with annually.

Try defending against that with a concealed pistol.