No, PTAsocial offers a secure private social network so only approved registered users will have access to the community events and news. This provides reassurance to those who are reluctant to share details in public forums like Facebook or open blogs. It's also great for people who might not want to mix 'home' friends with 'school' social circles.
As of May 2019, you can also choose to make specific event pages visible to the public so anyone can see what help is needed. However, in order to volunteer or view or post on the message wall, they'd have to register as a member.