[REBOL] Mutable natives

[lmecir]

How much mutable are Rebol natives?

See the following:

protect 'secure
system/error/script/type: ""
system/error/script/expect-arg: [
    (
        change pick third :secure 3 reduce [word! block!]
        secure allow
        "I love you"
    )
]
change pick third :secure 3 reduce [unset! none!]

; the results are:

>> secure throw
** : I love you.
** Where: secure throw
>> secure []
== [net allow file allow]

Regards
    Ladislav