I was going to say the same thing...
how many times has stuff fallen off a car because either someone forgot and left it there or a bolt wasn't tight enough...
we'd be having teams banned from races left and right...
in this weekends case, it could've been "oh i didn't lock the air flow hub in, it'll just spin till it breaks off car will be okay..." not "oh shit the nut isn't on, i'm not going to tell anyone"
I agree that accidents happen, and people make mistakes that's just a part of life. But there was no deliberate attempt to stop or caution Alonso that they had made a mistake so that he could pull off to the side of the track or at least try drive slower and get back into the pits. Alonso radioed in that something was wrong, and they said nothing to him. It was as if they were hoping to get away with it, and that is what the penalty is for.