>Example: two people starting to work on the same task in an offline-enabled task tracker. Wouldn't this just mean both people are working on it?

I agree that this means humans intervening.. It sounds like there was a comms breakdown. But rather than doing a first-in-best-dressed, it sounds like accurately recording that both users are in fact working on the same thing is the best option since it surfaces that intervention is required (or maybe its intentional, tools insisting that only one person can work on an item at once annoys me). Sounds much better than quietly blowing away one of the user's changes.

In principle, local-first to me means each instance (and the actions each user carries out on their instance) is sacrosanct. Server's job is to collate it, not decide what the Truth is (by first-in-best-dressed or otherwise).