All it is, is conformity, quite a lot of people still have a fear of flying or dislike it. If one person sees something adnormal which they did in this case, then others will hear about it and it will spread. You cannot blame them if they have a fear and all of a sudden hear that fuel is leaking, if didn't know any better i would be the first one off if someone saw that fuel was leaking.
In addition you can't say that they are over acting as you weren't in the situation, thus a number of mishaps may have lead up to the point of seeing fuel leaked. I.E taxing to faster than normal!