The maximum demonstrated crosswind is not limiting in the case of most flight manuals. Whilst your insurer will require you to obey such limits as G limits and others, figures such as the max demonstrated crosswind are informational only.
However... some clubs and syndicates do define maximum crosswind components, and insurers will sometimes specify that the aircraft should be operated in accordance with Syndicate/Club rules. If you find yourself outside the crosswind number under those circumstances, your insurance might be at risk.
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