DEs recognising one another?

[elirtai]

No: HPFGUIDX 36830

Naama wrote:
> Voldemort would never allow a mechanism that would enable one DE 
> to recognise another. Remember we're talking about a secret 
> organisation - for one member to potentially be able to point out 
ALL 
> other members means that one traitor can bring down the whole 
> organisation. 

I mostly agree with that. And think how they all are "hooded and 
masked" when they answer the summons... but shortly after that, 
Voldemort calls them all by their names.
(GoF chapter 33, "The Death Eaters").

Does that mean they already knew, rather than just suspected about 
each other? Or is Voldemort changing the modus operandi in his second 
rise to power?

Elirtai