"If a guest isn't married or in a serious relationship, it's perfectly acceptable to invite them solo," says one. In short, married couples, engaged couples and co-habiting couples must be invited together. Similarly, anyone in a long-term relationship should be afforded this courtesy, too. But, inviting a friend to bring along any old random is just asking for trouble.
When I got married in 1993, we invited my husband's ex-flatmate along with her current beau whom we had met on several occasions. Shortly before our wedding this woman broke up with the gentleman named on the invitation and she asked if she could bring along her new boyfriend instead.
It was an awkward scenario. There were all sorts of factors to consider. We hadn't met this new guy. We didn't even know his name. I thought it would be odd to be introduced to someone at your own wedding. Wanting an intimate affair with just family and close friends, we had invited only 80 or so people. Exchanging our vows in front of a stranger struck me as odd.
I also recognised that this woman had done the civilised thing in asking us. She could have just presumed it would be okay and brought him along without consultation. I was aware that the relaxed and friendly thing to do would have been to say yes. It would have smoothed things over and eased a slightly uncomfortable situation.
But we (okay, it was mainly me) said no. I might well have boycotted the event if I'd been in her shoes but this woman attended our wedding on her own. I momentarily felt guilty about it because she didn't know many other people present but I soon put it behind me.
I might not have remembered this set of circumstances at all were it not for a chance encounter at a barbecue a few years later. The cover of a local magazine that week showed a B-list celebrity marrying a dark-haired man.
"I know that guy. I sort of used to go out with him," I said.
"So did I," replied the woman forced to fly solo at my wedding.
I was so surprised. What was the likelihood of that? It was something we would never had discovered had his larger-than-life-size face not been plastered on signage in dairies all over the country. We discussed the dates of our respective liaisons. I'd known him briefly and very casually many years before. My wedding guest, however, had dated him more recently and much more seriously.
We talked some more and, sure enough, it transpired that this was the man who would have been her partner at my wedding had I agreed to the suggested swap. Now, I can think of few less desirable surprise wedding guests than someone you met in a dim, dark Wellington nightclub and shared a few late-night drinks with on a couple of occasions.
He would have been the last person I expected to see at my wedding. In fact he would have been in the top three least desirable guests I could have imagined. I reckon I would have had trouble figuring out where I knew him from and then would have felt distinctly uncomfortable once I remembered.
All of a sudden, I felt vindicated. My policy about substitute guests may have been stringent and unaccommodating but, in light of fresh intelligence, it was looking increasingly wise. Allow anonymous guests at your peril. You'll never know who might turn up to your special day. You have been warned.