The allotment for the locals presale is 10,000 tickets. I expect it will sell out before the endof the day, but whether some of those purchases are just intended for resale at a profit is anyone's guess.
The Advocate this morning
mentioned that on Stones day, no chairs or tarps will be allowed at the stage where the Stones play. Given how much extra space those take up, this should allow them to sell a lot more tickets (75K instead of 50K?), and perhaps ease demand a bit. But I think that day does still sell out.
I think calling Hancock a Parish was a tongue in cheek way to emphasize that they're so close to Louisiana? But limiting "locals" by state is just logistically easier. It's simple for the clerk at the ticket office to see what state a license is from; it's much harder and slower to verify what county/parish a specific address is in, or whether it's within x miles of 70119.