Princess wears tennis shoes every day, once in a while I let her wear her crocks. She's a kid, she runs around, we walk to and from school and I feel she needs to be wearing shoes that support her feet.
I love flip flops but I don't think there appropriate for kids to wear to school (elementary school). These kids are going to end up with foot problems and flat arches (among other things). Not to mention, flip flops offer no protection if you fall down or drop something on your foot.
Some parents just annoy me...