Does it annoy you when strangers do this?

I was in a shop today with my baby in her pram and my 4 year old...well I was stressed out as baby was yelling...shop was crowded etc...my 4 year old had her thumb in her mouth...bad I know...I am always telling her to take it out and the dentist has also told her...bt this elderly lady came up and shook her finger at my daughter and said "No, no no! You mustn't do that or your teeth will stick out!" It really annoyed me as my daughter is VERY sensitive and also wary of ALL strangers....it's just her personality....some strange lady coming up like that frightened her....I never said a word...which indicated my displeasure far better than having a go at the lady (who I am sure meant no harm) it is not a strangers place to tell my child this sort of thing,...and in doing it she basically disregarded MY authority....if I want my child to take her thumb out I will tell her...nobody else...do you know what I mean?