I'm so glad it wasn't a wedding. Software can usually recover these things, but for some reason, not this time.
Rest assured, I learned my lesson. Never again.
Aaron and Katie were so good to humor me and repeat the session, same time, same place, same clothing, one week later. *Which* all ended up being a good thing, because little Miss Em was a bazillion times happier in the second shoot, so it's a win-win for all involved!