I don’t think the no kids thing is any more of an issue than as PP said a mid-week wedding, or a wedding that requires an overnight stay. There are so many things that couples choose for their big day that cannot suit every invitee.
My friend had a midweek wedding, that required a 2 night stay, with no kids, mid-week, in the middle of the 6 weeks holidays.
She was most affronted that some people ‘didn’t care enough to make the effort to come’, including those that would be coming from the 4 corners of the UK and Ireland.
I tried to explain to her that for some people it would have been nigh on impossible, especially when you are talking about family whose childcare options would have actually been attending her wedding. People have their own family holidays over that period, might struggle to get time off from work, the expense itself of attending, not wanting to leave your kids for 2 nights if they are young etc etc.
When you are child free you really don’t understand what you are asking of people. But couples need to understand their choices might mean some people can’t/don’t come, and invitees have to accept that they don’t get to dictate the arrangements to suit them and accept or decline on that basis.
I can’t bear it when people say things like ‘we come as a family’ or ‘if you don’t want my kids there then I’m not coming either’, or equally when people say things such as my friend above. They are such selfish things to say. The world revolves around no one so get over yourselves!