Playground Crash...

So, my wife was at the playground recently with the kids, who were playing nicely, first by themselves, and then with other kids at the park. Now, it's important to note that she is White, I am not, and our kids' skin is pretty brown. As the kids played, she engages in conversation with another woman who is supervising kids at the playgorund. It's important to note that this woman (listed below as OW) is also White. Here's a liberally-transcribed version of the conversation:

OW "Wow, the kids are really playing well with each other."
Wife "Yeah, they pretty much get along well with everybody."
OW "Are they your kids, or are you the nanny?"

OK, from both Black-power and level playing field perspectives, I would LOVE to say that my dark-skinned children have a White nanny! How George Jefferson would THAT be? But alas, my chosen career field, which keeps me emotionally and socially happy, prevents me from hiring a nanny of any race or ethnicity.

So here's the essential question: Why does a mother at a park with children who don't phenotypically resemble her have to be the alternate (i.e. non-parental) caregiver? Why do we, especially in this part of the country (the Northeast), where there is a prevalence of bi- and multi-racial children (not to mention trans-racial adoptees), still assume that children have to share the same melanin concentration as their parents? It's amazing to me that White privilege rears its head in so many unexpected places.

So, yeah, while there was no violence, I'd call this a crash. Wish I was there when my wife said to this person - "No, they're mine; do they not look like they're mine?" - so I could see how many shades of red this person turned.