Aesop has a way with words:
http://raconteurreport.blogspot.com/...e-got-hat.html
I told you that to tell you this:
Option I:
You're Michael Mann. You've got a 150-person crew on union rates. You've got 200 extras. Including 50 cop extras with working firearms props. Some of them are stuntmen. You've got seven cameras with full crews, and a 20-man special effects and pyrotechnician crew. You're going to be blowing out building windows, car windows, blowing out tires on police cars, you've got stunt drivers, 20 guys from LAPD on double holiday overtime to lock up traffic from four main streets, in downtown, on a weekend, and the sun is moving across the sky at 15° an hour no matter what you do. And no matter what, you're literally setting $500K/day on fire, whether you get the scene or not, before you think about location rentals, caterers, parking, and 300 other things. And suddenly, your ten lead actors all decide they're going to double-double check their weapons, because some Good Idea Fairies on the internet thought that was a cunning plan. Three of your guys, with no expertise, after the weapons were loaded and prepped by a team of the top weapons experts in Hollywood, which is to say, in the world, had them ready to rock, but your hamfisted actors managed to short-stroke a couple, and they jam; one guys' doesn't fire at all, because he can't get it back into battery. And by the time you've got your 200-piece orchestra all ready to try Take 2, you've just burned through an hour, plus 10% of your weapons budget for ammunition, glass, tires, and other special effects. And the Good Idea Fairy has become the Fuck-Up Fairy, and it's sitting on your face, and shitting right in your mouth. And this time, half the extras who're cops decide they should check THEIR weapons too. Now you're up to Take 3, and you're seriously wondering if it wouldn't be cheaper to hire retards for the extras, and just hand out live rounds to the principal actors, and get the whole scene in one take. By Take 4, you're spinning a revolver with 5 loaded bullets, and one empty cylinder, and you're ready to squeeze the trigger.