I agree with Nitric in his reply. I would add a couple of things, what I do not do is bring a SHOVEL to dig with, school grounds or parks, looks really bad, just my simple digging knife with a orange handle. As Nitric said, just don't make a mess, and of course take any trash targets with you. I carry a small plastic bucket with me for that, and even pick up water bottle caps etc. as I go along. I've never had a problem anywhere. Schools other then public, private, catholic schools etc., I would say you do need an OK for those. If the grass is nice, and the ground is "summer dry", I'll come back in the fall, no good way to dig a plug in super dry ground without risking damage. When there IS school going on, weekends only. I have only been approached one time, and here's a small tip, I always carry two rounds of live ammo in another pocket in my coin pouch that I have dug before, one is a .22 long that had been hit by a lawn mower, I showed the fella the trash in my bucket, and mentioned and showed him the two rounds, and as he left he hoped I'd find something good. I understand everywhere is different though, and IF asked to leave, well.....OK