They got hit. They didn't get kidnapped. You don't want this to happen to you, but chances are not big. It just depends on the guerilla's agenda it seems. On some occasions they don't make problems, on others they do.
Most travelers never have any kind of problem.
Travelers are basically not a target. However, things have been deteriorating and will probably get worse before they get better, so you should definitely avoid running into guerilla. It's not very hard to avoid the few dangerous areas, which will decrease the guerilla risk to almost zero. Colombia is a beautiful country. It's people are amazingly nice.