my parents arrived on 07-10-2008 on B2, 6 month stay granted. On 12-08-2008, extension petition for another 6 month filed, but denied (marked 04-16-2009).
They already booked tickets leave US on 06-15-2009.
(1) If they leave as planed (on 06-15), their accumulated unlawful days will be less than 180 days, and there is no bar for them to apply new visa, right?

(2) Do they need to inform USCIS when they leave US?
How?
(3) Need to show any documents (like extension application) if they apply for a new visa? and when they enter US if their new visa granted.
(4) Will this deny impact on their applying new visa after several years?
(5) How about submit a motion to reopen? Will it make their status after 30 days pass 05-15-2009 legal (date they are require to leave in deny letter)?