What about the Bar?
Indeed. The above post pretty much answers the law school portion of your question, but what about the bar? The moral character application (at least here in CA) involves a FAR more thorough background check.
The law schools pretty much take you at your word that you haven't done anything wrong. The bar does not. They will check your records, contact people, and note discrepancies. Also, I seem to remember that some states will ask a catchall question, something like "Is there anything else that you feel you should disclose?"
Remember, the bar will compare your law schools apps and your bar app.
The general rule is disclose, disclose, disclose. The bar can be forgiving of previous mistakes, but not of attempts to cover them up. Actions which indicate dishonesty are taken VERY seriously.
Nor will they have much patience for excuses. Lot's of people have a tough time at home, and yet they manage to get through college without cheating. As a bar applicant you are asking to be entrusted with people's lives and livelihoods, and they want to know that you are mature and honest.
Are you required
to disclose? I don't know, check with your state's bar.