I have been invited to several black tie weddings including two that were outside. I have two this fall. I’m OK with this because I own a tuxedo (I bought it for a New Year’s Eve event we go to in some years but even there many men wear dark suits) and my adult son (now 31) has attended the weddings (and the NY Eve event) wearing a dark suit and many other people did as well. Not an issue for men. I think women need to wear fancier dresses, which may be an issue. Personally, I prefer shorts and sandals, but I haven’t been to a wedding where that was OK.
Weddings have become such a weird industry. ShawD was just asked to be the maid of honor at her HS best friend’s wedding (we are friends with the bride-to-be and her parents as we almost co-parented the two girls in HS). She got a pre-packaged gift pack with the invitation as did the other bridesmaids. The wedding websites now feature an obligatory photo of the groom on his knees proposing so you have to plan an event and hire a photographer and/or videographer for that. And on and on.
Black tie is much lower on the list of wedding silliness but there is no reason to go if you aren’t comfortable.