wojtek --------------
I think that is a mistake. I think the rules of evidence, what is admissible and what isn't are looser making it easier to gain reasonable suspicion. There is no cross-examination, so the witnesses are not tested for creditibility. I don't know about the rules of discovery. You can have a lawyer with you. They sit, watch, take notes, maybe confer with you, but they play no active role in the proceedings.
This comes up in context of the Penn State Sandusky case. In this context, it was probably a wise decision to use the grand jury system, primarily to protect the identities of the boys involved and gain access to evidence that is usually not allowed, hearsay, for example. He told me such and such.
CG