How to apply the doctrine of 'accident insurance' cautiously?

Estey J. also cited with approval the following statement of Lindley L.J. with respect to the need to apply the doctrine cautiously, in Cornish v. Accident Insurance Company (1889), 23 Q.B. 453 (C.A.), at page 456: In a case on the line, in a case of real doubt, the policy ought to be construed most strongly against the insurers; they frame the policy and insert the exceptions. But this principle ought only to be applied for the purpose of removing a doubt, not for the purpose of creating a doubt, or magnifying an ambiguity, when the circumstances of the case raise no real difficulty.