If they don’t want to go, then make their excuse and decline!
Weddings are strange things where the guests appear to be divided into groups His, Hers, Their friends, Inlaws, Outlaws, Her work mates, His etc.....
We were invited A few years ago to a neighbours daughter’s evening do. Arrived at stated time with others to find the afternoon reception had over run & the speeches were still underway in the marquee. We were taken into the house & given a glass of bubbly for an hour (One glass ?) and made awkward conversation with other evening guests. Once ensconced in the marquee where chaos ensued and discovering we had to purchase any further drinks at the bar, we sat it out for 30 minutes feeling like the poor relations then DH & I looked at each other, winked and beat a hasty retreat, via a flap in the marquee, back home for an evening in front of the telly and an omelette for supper Oh the relief ?
Needless to say at our 3 daughter's weddings, although all very different, guests were invited for the whole shaboodle!