Because having an au pair seems to be considered posh.I have one out of need,not out of choice.
DC2 has SN and health problems which could very well mean a midnight ambulance trip (already once this week and its only Tuesday),so by having an AP it means precious time is not wasted in getting a babysitter,as DH travels a lot.Also there are many appointments,so it means I can go and not have the other children distracting me or annoying anyone.
But no,to others I have an AP because I'm posh.
More of a rant than AIBU.