With third-party code, you're always relying on the best effort of others. Of course a version number doesn't relieve you of the need to run tests on your code

With third-party code, you're always relying on the best effort of others. Of course a version number doesn't relieve you of the need to run tests on your code base, but the probability for semver issues and code bugs should be about equally high - so there's no reason to trust one but not the other.