Dress code for proms?

[Posey]

Have managed to get tickets for mum and dad for mum's birthday. It will be a srprise while they are staying here. But I need to know if I need to tell them to pack anything special. Would my dad need a tie? Suit?
Thanks for your help.

No dress code - very democratic. Both in the seats and in the arena lots of people come straight from work so are reasonably smart but there are plenty of others who aren't. In certain sections of the audience the shorts and sandals look is often in - but frankly its not that attractive in middle aged, overweight men with hairy legs.

Oh thanks for that! Don't remember ever seeing my dad in shorts so thats okay then! I really didn't want to have to tell them to bring something special as then half the surprise would go.
Thank you!