Hahahaha...now I don't know whether to tell you not to be afraid or not because this happens to me like all the time. Moat times when I even come across is, I would tap someone by my side and ask him or her to look at it as that may be the first and last time he or she would be seeing such. It's funny to see that it happens to you too but I have never ascribed any meaning to it.

It might have a meaning, it might not...but I just always let it pass. It's a good thing that you have brought it up. Mayb someone here might have a reasonable explanation .