Why did I get notified who added me 2 their new buddy list? if i add someone will i tell them i did too?

someone on my bl made a new sn, they didnt tell me they did but i received a notification saying so and so added you to their buddy list...y did it tell me this ...i know i dont want aim notifiying everyone who i add to my list some people i dont like and dont want them to know theyr on my list...why did it do this and will it tell whoever i add too?