Perhaps, but it depends on why and how it's used. Nearly every operating system is wide open if you have physical access to the machine. I can't think of a single operating system which isn't simple to get into as root/administrator as at the console. For example, in Windows you boot in safe mode or command prompt. For Unix variants, you boot in single user mode.
More important security concerns would be things like memory locking, muliuser file permissions, etc, providing that you were using the amiga as a multiuser system.
Since the Amiga isn't really a Multiuser system, nor is it used remotely, there isn't much left to secure *except* a login at the console. A boot password in the roms themselves would be the only good solution that I can think of.
