No, they almost certainly wouldn’t be unless one of the group happens to be a lawyer with experience in that area. But in such a case, the grand jury probably shouldn’t be aware - or need to be aware - of that fact.
Recall that for grand juries we’re talking about felonies, not petty crimes. I’m sure that there are a number of felonies on the books that should not be there, but in general I don’t think that there are a lot of felony crimes that are “routinely ignored”.
But regardless, the grand jury is there to validate that enough evidence has been collected to ensure that arresting and jailing a person is justified. They are not there to decide whether the laws are valid, and they don’t determine whether the subject is guilty or innocent.
What the grand jury should be doing is questioning the evidence, and they often do that.
Anecdotal Story
A quick anecdote: I was on a federal grand jury for a year (one week each month), and we heard a hacking case where the accused had allegedly broken into a slew of government computers. To make it a felony, the perpetrator had to have caused $X amount of damage to the public, be that in damaged hardware or lost productivity or whatever.
In this case, the hacker found some default passwords still on the boxes and used those to gain access. He then did a bunch of damage inside. But the prosecutor in this case cited the fact that after the break-in, the agencies in question were panicked into doing a massive effort to plug all those holes – they hired a contractor to scan all their servers and fix the issues, and the effort cost multiple millions of dollars.
The prosecutor pointed to that cost as part of the reason that the indictment should be a felony.
I - a guy having some insight into government computers - pointed out that government regs mandate that any new server should be configured to remove the default passwords. The hacker didn’t cause the issue, his intrusion simply brought to light a bunch of poor configuration-management on the part of the government; those millions of dollars would have had to been spent regardless.
Man, the prosecutor did NOT like that. He proceeded to lecture me on how expensive government contractors were… which was ironic since a good third of the jury were government contractors. And he elected to leave that evidence in the indictment and ignore my comments.
I eventually voted to indict anyway, because the cost of the actual damage that the guy did was still above the threshold. But I was somewhat gratified to learn later on that the judge threw out the specific counts related to those charges… for exactly the reasons I had specified.
