Hadn't thought of that angle before, but sounds plausible.

My initial hunch was a well-intentioned but naive and judgmentally-impaired teacher of the "No child left behind" mentality thought it would be a crime to leave an under-privileged kid behind just because he never had swimming lessons before.  You know the type, the ones who favour "No fail" policies because it's hard on the kids' self-esteem.  Stupid, but it would get some sympathy in some corners.

If your hunch is correct, wow; just wow.