ironpony wrote:
Yeah true, but who would they be asking where they were on a certain date? Asking Epstein?
In most court cases they do this to confirm a person was at a certain place where an event is alleged to occur. In answer to this (or from a related to questions either from prosecution or defence) about "was there anyone with you" (or similar lines of questioning) unfortunate details may be revealed.
If they don't ask if they were there, then in closing it can be argued that they prosecution never provided proof "beyond reasonable doubt" of the person being somewhere when an event occurred (or defence may ask questions which elicit this type of information - "Person XYZ was there as well, and it was they who must have committed the act", for example).
During a criminal trial, the defence are the only ones who can (in general) spring surprise information, as prosecution has to supply most information to the defence which may have the ability to be used to defend against charges, while defence don't have to produce anything until the trial...