Note that in the OpenSSL case at least, this check is in the default engine/plugin, not in generic code. If you load a different plugin, you only get protection

Note that in the OpenSSL case at least, this check is in the default engine/plugin, not in generic code. If you load a different plugin, you only get protection if the engine/plugin implements a similar check internally. (I expect that LibreSSL removed the plugin framework, but I haven't checked.)