Is there something special about mount points in / ?

[Dr Lyman Hazelton]

I have set vfs.usermount=1, and now I can create a local directory 
(call it "xxx") in my home dir and use it successfully to do

mount -t cd9660 /dev/cd0 xxx

or 

mount -t msdos /dev/fd0 xxx

However, if I attempt to use the "standard" mount points, /cdrom or 
/floppy, to do the same thing, like

mount -t cd9660 /dev/cd0 /cdrom

I get the message: cd9660: /dev/cd0: Operation not permitted.

I have set the permissions on /cdrom to 555 and the file is owned by 
root:operators, and my non-root user-id is a member of operators.  Is 
there something special I have to do to /cdrom to make it usable to 
non-root users?  What ever it is, it must be the same problem I am 
having with /floppy and my sound system, so solving this will solve a 
lot of related problems.

Thanks for any and all assistance.

       -Lyman