That kind of depends on the circumstances though, doesn't it? If someone on the street snatched your wallet out of your hands, and you felt reasonably confident that you'd be able to safely reclaim it by wrestling it back out of their hands, wouldn't you? I'm personally not very strong or fast, and I don't have any skills in terms of identifying whether someone might have a knife or something, so chances are that I wouldn't feel confident in pulling it off. If I did happen to have enough confidence that I would be able to without getting hurt though, it certainly feels like I'd be justified in doing it, and it seems like it would be more desirable than letting them take my wallet.