I wasn't offended by lack of a physical invitation, but a friend of mine got married and invited my wife and I in a very informal way with a text message. We en

I wasn't offended by lack of a physical invitation, but a friend of mine got married and invited my wife and I in a very informal way with a text message. We ended up waiting until way too late to book tickets, because my wife was expecting a physical invitation to follow the informal SMS save-the-date, and we ended up missing the wedding because flights got ungodly expensive (and involved many complicated connections). Anyway, it's not totally relevant to the main story here, since that was very obviously a "This is the official invitation/confirmation" thing, but I think it's worth considering that if you are going to buck tradition, you should try to be absolutely clear that that's what you're doing so that people can adjust.