OT: USB stick with write protect switch?

[Colin Law]

2009/10/12 Amedee Van Gasse (u2s) <amedee-ubuntu at amedee.be>:
> On Sat, October 10, 2009 22:16, Colin Law wrote:
>> If the switch disables the write signal directly then it will be
>> impossible to write to the device.  Though there are still three ways
>> that I can think of that this method might still allow writing, one is
>> hardware failure (broken switch or similar), the second is
>> accidentally moving the switch (or maliciously I suppose) and the
>> third is Divine Intervention.  Whether this therefore counts as a
>> write protection method that *always* works is a matter of
>> interpretation.
>
> I can think of a fourth way:
> The C-x M-c M-butterfly command in Emacs...

For those of us unfamiliar with Emacs, could you elucidate?

Colin