It is a thoughtless but people don't usually mean to be. I wouldn't agree to be a backstop in case someone else doesn't turn up unless you really want the chance to be there.
I would let this one go but if it happens too often I would say something.
It is unfortunate but it can be a bit uncomfortable to feel that you should be grateful or are beholden to people even if you have never expected that.
Move on to your own plans and look forward to whatever you do decide to do.
Last weekend, in Rutland, the first statue in Britain of the late Elizabeth II was unveiled.