IMHO, you don't wnat to spend money on a supplemental policy that covers you for only a limited range of risk, i.e. an accident, or an accident in a bike race.
From a financial planning point of view, you need health insurance, you need disability insurance, and if others depend on your income you need life insurance.
You need all these things regardless of whether you are killed or disabled by a bike wreck, or by cancer.
Thus buy appropriate levels of health, disability, and life insurance, and don't waste your money on supplemental accident insurance.
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You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.