But if there's no disclaimer at all, then someone can sue you, even if the whole case is BS and the software you contributed to wasn't at fault. It's still something you'd have to deal with. Never contribute to something that doesn't have this sort of disclaimer- it means both that you would be leaving yourself open to lawsuits (justified or not), and that the people running the project don't know what they're doing.
If an open source project in this area doesn't have a disclaimer like this, the people running that project are clueless, and if they're clueless about that, they're almost certainly clueless about the much more complicated technical stuff, so it wouldn't be a project which would be desirable to contribute to in the first place.
If an open source project in this area doesn't have a disclaimer like this, the people running that project are clueless, and if they're clueless about that, they're almost certainly clueless about the much more complicated technical stuff, so it wouldn't be a project which would be desirable to contribute to in the first place.