Many end up being called a "one night stand" simply because sex only occurred once overnight, it doesn't mean it was intentional that there would be no follow up at the time and for many people like myself it's something that has only happened on a few occasions throughout their life. I'm 48 for instance and I've only had sex with a girl as a one off without it leading to a relationship twice which isn't much at all and on both occasions I didn't know whether it would lead further or not at the time. It's not the same as people who go out regularly looking for a casual partner just for 1 night, then another the next night without having any intention of having any relationship with any of them. There's quite a few people around like that, but I suspect there's a lower proportion who are on the autistic spectrum.
Anyway is there really anything wrong even with intentional one night stands? If both consenting adults are happy for a no ties sexual encounter and they're responsible enough to take the relevant precautions, then I say let them enjoy themselves if that's what they truly want out of life at the time, they're not harming anyone. Yes I understand that casual sex is against some people's etiquette and values, so if they wish to live by rules such as "no sex unless in a serious relationship" or even "no sex before marriage" then that's perfectly fine, but it's unfair for them to attempt to enforce this on other people who feel differently or even condemn them. This is the 21st century.
