""I find it hard to imagine a situation in which a legal case would hinge on a simple grammatical error. Do you know of such a case?""

Not so much court cases, but I do know of some contracts invalidated by misplaced punctuation and grammatical error.

An uncle of mine who was in the property business had to refuse the services of one partner in the law firm he used, for that very reason, and came very close to severing his contact with the firm as a whole.

Had anyone invoked the terms of those in a legal action, I'm not sure what the outcome might be.

Don T.