I did it to my 2 sisters my cousin ,ante,brother,mother and my 5 year old neice and 3 year old nephew all today or last night.They all got scared to a certain degree except my nephew who accually laughed at it.My 22 year old sister was the one who was most scared she not only jumped but let out a little scream.
I think that proved that some people are just more scared about ugly faces and load noises than others.
I did it to my neice and nephew with their mothers permission.