We passed a church the other day where a wedding party was just bursting out. Amongst the posh frocks and decent shirts and trousers there was a handful of men wearing jeans, trainers and sweatshirts. No, none of them designer, unless you count Primarni, and none of them even remotely smart. Turning up to a wedding looking as if you've just rolled out of bed is an insult to the couple and their family, IMHO, as well as to your own partner (all the women had made a real effort).
Having to dress up for a tourist attraction is a step too far, though!