[syslinux] ALLOWOPTIONS directive

[Ady]

I have some questions about "ALLOWOPTIONS 0".

[quote]
ALLOWOPTIONS flag_val 
If flag_val is 0, the user is not allowed to specify any arguments on 
the kernel command line. The only options recognized are those 
specified in an APPEND) statement. The default is 1.
[/quote]

My understanding of the behavior of "ALLOWOPTIONS 0" is that unless I 
type-in a command that is exactly the same as the result of executing 
a label, then the command is "not accepted" ("not allowed").

 1_ Is my understanding correct?

 2_ Are there any cases in which the resulting behavior is different 
from using the IMPLICIT directive (with respective labels)?

While using 'ALLOWOPTIONS 0'...
  3_ Should typing-in a 'label' (instead of the whole equivalent 
command) be accepted too?

  4_ If I type-in a 'label' in the CLI, should additional options be 
allowed?

  5_ If I press Tab in [vesa]menu.c32 and delete part of the command, 
is the resulting command allowed?

  6_ How exactly is a command "not accepted"? What happens then? Is 
the entire command rejected? Or is the typed-in kernel executed 
without options? Or is the DEFAULT command executed (without 
options)? Or is the ONERROR command executed (without options)? Or is 
the first label found with "similar" options executed? Or...?

The reason I am asking these questions is because I am testing 
"ALLOWOPTIONS 0" and I am slightly confused by the result. Knowing 
what I am supposed to expect would help me test the directive 
accordingly.

TIA,
Ady.