The "and guest" may be more and more usual today, but that doesn't make right.
More and more people here write "anyways", which isn't even a word, when they mean ANYWAY. Because it is now used more and more, does that then make it correct?
And if cousin so and so shows up with some stranger, THAT IS RUDE and while a place and food would somehow be found,I guess.But it would NOT be me, who would be ashamed at having him/her thrown out. The cousin should have alerted whomever was throwing the wedding...even IF it was a very informal wedding.
Your response doesn't negate anything I said in my post you replied to. There is nothing rude about inviting "___ and guest". Nothing. You can't even make up a reasonable scenario where it's rude to invite single people that way if you don't necessarily know their current relationship situation or what it might be a few months down the road.
I just don't get why the concept so alarms you.
Earlier you said you'd expect the wedding planner who is supposedly running around with a clipboard and a list, to boot out anyone she didn't find on the list... or move them if they sat at the wrong table... That's what I was responding to. If it were my wedding and I found out anyone was treated that way I'd be appalled. The best laid plans can be thrown on the fire before I'd let that happen.