Exactly this for me, same as i don't ask them anything when they buy something and i must sign for it.Actually, 99% of the time I'm not even saying anything, me mum just takes it in lays it on on the table.
Much like all of me mail.
To everyone that is an adult and has to deal with parents.
You're a fucking adult.
Tell them it's your life and your mail and that they have no business interfering in it.
Tell them you grew up and can take care of your self.
I'll do that next time I buy a flash card! I will take you up on thathow about you tell your parents you won a prize from an online forum?
if they ask for proof, tell them to contact me