Well, no. That's why we have an access control system which kind of makes it hard to enter if you don't have an access card. And only members have access cards.
Obviously, there's always a small chance of someone just walking in after a member who just opened one of the doors. This is where the community comes in. We rely on members not to let in people they don't know.
Basically, if someone is trying to sneak in with you, don't hesitate to stop them and ask them where they are going to. If you think they are trying to bullshit you, don't hesitate to decline them access and instruct them to go to reception.