I mean do the admin there test it if it's safe or not before posting the plugin? Sorry if I asked this WP newbie here.
Yes they do test them all. Even a rouge plugin will not do that much damage. If you do end up with the dreaded wordpress white screen of death and cant access your site/admin panel, all you need to do is open your FTP and delete that plugins folder, which should restore everything. Ive had a few problem plugins, mainly to do with being incompatible with my version of Wordpress. Its never been too much of a problem though