Situations vary, but the majority of my kayaking has been in waters far too shallow or turbulent for conventional craft -sea caves, for instance. And when a paddler is in more conventional situations, keep a sharp lookout.
On board larger vessels, I have been startled numerous times by the sudden appearance of smaller paddlecraft and vessels, typically displaying no lights at all, even under dusky conditions.
Strobe lights-there is some variation. This source states strobe are for inland waters -at 50-70 flashes per minute. Others don't make that distinction. Can't you just picture the Gary Larson cartoon with the caption "He must be OK. He's only flashing 48 times a minute."
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Geezer in Chief