Probably accurate in the case of my future MiL, but that's another matter.
I have two younger brothers and no sisters, and we're all closer to our Mum than our Dad anyway - it feels like a nice opportunity to get her more closely involved in the day, however unusual it might be.
My partner and I have been considering this and how it applies to our wedding when it happens - I'm considering flipping things around and having my Mum walk me down the aisle.