Command Computer Restrictions

I haven't yet played with Command Computers, but they look really cool

I just have a question on their restrictions. I know they are a creative-only item, but once they are in the world, can just anyone come up and program
something? If so, that kind of seems like a security loop hole.

Vanilla command blocks require you to be in creative (and maybe opped too, I can't remember)
Just checked, you do need to be op

You need to be opped and in creative mode to use them. You can't even get to the terminal without it. There are some things non-opped players can do as detailed by this bug report. You might want to surround it with lava and bedrock (and lots to prevent enderpearling in), etc… to prevent people accessing it if on a server.