Still, most marathons do their best to protect everyone involved, said Virginia Brophy Achman, executive director of Twin Cities in Motion, which organizes the Twin Cities Marathon, the country's ninth largest.
The Twin Cities Marathon has a crisis plan that gets reassessed every year, Brophy Achman said, when race representatives and city officials run through a list of "what ifs," from bombs to fires to floods to extreme heat. Canine units sweep the finish line several times during the weekend of the fall race and the area is covered by security during set-up and teardown.
The marathon world is widely collaborative, she said. Her organization has shared its crisis manual with other races across the country.
"Safety is always first and foremost our top priority -- for runners, spectators and the community," Brophy Achman said. "Our eyes and ears are on high alert on race day. We're always aware of what's around us."
To fill in whatever gaps might be left by lapses in law enforcement, Roman said, runners can help protect themselves by cultivating awareness of their surroundings. Stay away from large crowds, for example. Skip the triage area at the finish line and arrange instead to meet a family member with Gatorade and ice packs a few blocks away.