Shared Pensieves? (was Re: Snape's access to DD office?)

[potioncat]

No: HPFGUIDX 108257

Becky wrote:
> 
> 
> What I have always found curious is why wizards don't seem to use 
them
> in trials to prove innocence (or guilt). I suppose it's because the
> remember-er could skew the memories (something that I feel may have
> affected Harry's view of his father in Snape's mind.)
> 

Potioncat:
The two cases where we see a Pensieve used, the individual chooses 
which memories to take out of his head and put into the Pensieve.  
How would another wizard get into someone's head to get out the 
appropriate memories?