Listener email: Wedding invite- 'Single or not, should it not be good etiquette to allow a plus 1?'

A listener got in touch: 'What would listeners opinion be on receiving a wedding invite and a plus 1 was not included on the invite? I'm a single 30yr old female, and an invite I received has no plus 1 that I can bring along with me. Single or not, should it not be good etiquette to allow a plus 1? Thanks, Anon' What do you think? Ciara hears from listeners