When I make appointments for the kids I always say "Hello, this is Sherie Brown, I'd like to make an appointment for my son Lindsay" and they will ask 99.9% of the time "is his surname Brown too".

As much as it annoys me, I suppose it is just a reflection of today's world where many couples are not married (either by choice or are too young), or choose to use hyphenated names, blended families etc. You can't blame them though, it is just them making sure they have the right details because you can't assume anything about anyone these days.