The fact that they had time to slowly walk 20 feet away from the train before you passed them probably suggests there wasn't much real danger. 
Can it result in danger? Yes, if they stay on the tracks. But then look at something like Jaywalking, you wouldn't do it if the road was busy, but it's normally fine if the roads empty or the only car is way off.

Calculated risks, and since they not only got 20 feet away beforehand, but they slowly got there? 
I honestly don't think they were doing anything that stupid.