Would you like a shirt to go with that?
I dunno, it’s a bit casual even for a McDonald’s birthday party isn’t it? Especially one celebrating 40 years of two all beef patties etc etc on a sesame seed bun. In fact I don’t think it’s ever appropriate for any 40th birthday celebration unless of course the guest of honor runs some kind of raunchy, adult-themed safari tour business.
No shirt, no shoes, no service!