I defer to those of you from the US re the law here. However, I suggest that
irrespective of the law itself, there are also university wide policies. At my
University for example, all surveys require human subjects approval. I have
always operated on the basis that I would much rather err on the side of the
cautious here. If nothing else, it would be the height of embarressing to get
hauled over the coals on something like this. I have even gotten approval where
I am doing something entirely for an outside body but my name remains
associated with U of W. Neither the Office of Research nor myself knew whether
it was necessary, but it certainly did not hurt going through the motions.

Since the object of these rules is the protection of the subject (particularly
for children and for any kind of intrusive physical investigation eg medical)
and since informed consent is at the heart of this particular execise, I cannot
imagine that going through this process will be anything other than pro forma.
But check this out anyway as there may well be variations between schools.

Sally