Parallels global sharing: now an XP virus can destroy your Mac

By now quite a few people have noticed that OS X Parallels beta allows a non-admin user to read-write-delete anything on the drive. A recent statement on the Parallels blog feels a bit defensive:

The Official Parallels Virtualization Blog: Upgrade your XP virtual machine to Vista with RC3

Global Sharing shares the your entire Mac file system. It is important to note that Global Sharing is DISABLED by default.

A malign XP process can now destroy an entire OS X system. I don't understand why there's not more of a fuss about this. Of course I'll disable "global sharing", but the affair forces me to recognize how extensively Parallels bypasses OS X. I wish Apple were interested in doing a virtualization layer that respected the primary OS ...