Drowning detection, pool surveillance with Poseidon
This is from an advertisement:

Poseidon is the lifeguard's third eye that never blinks. It uses advanced computer vision technology to analyze activity in the pool, captured by a network of cameras mounted both above and below the surface of the pool. Poseidon helps lifeguards monitor swimmers' trajectories, and can alert them in seconds to a swimmer in trouble...The Poseidon System will soon feature an optional “After Hours Intrusion” mode. Designed to detect the presence of one or more swimmers, the alarm can be configured to sound locally, at a police station or other security monitoring station.

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If such a technology exists, is there a duty to install it if the HOA can afford it, as in a big and well-funded place with no lifeguard on duty? And how would people feel knowing that they are being watched from below as they swim, by a "third eye that never blinks"?