Hi Mike,
Here in Tassie we have to get a permit from the Parks and Recreation department of the local council, the restrictions are, we are not permitted to dig holes (They canned all the detector people about two years ago from digging holes as it left little dead patches all over the lawns), so I just search with the SE sensitivity set at 5 and use a pointed screwdriver to probe the soil if I can feel the target with the screwdriver and it's a bit deep I use a pair of medical forceps to pull it out of the ground therefore no holes and everyones happy. I also take all the junk with me and initially they would only grant the permit for six months so I sent them a picture of all the junk I had extracted from the parks and they were thrilled to bits and sent me back a permit for twelve months. I live in Launceston and sent the same info to the Hobart city council and they also granted me a permit to do the parks in Hobart, the only other request they made, was to be informed if I found anything of historical significance. As for soft ground, there is plenty of water here, so they water the grounds every morning, in fact I have been caught under the sprinklers from time to time. No I don't get hassled by anyone, all the council worker seem to be a pretty friendly bunch and will stop and have a yarn with you, I also get a lot of interest from other park users so all round it's pretty good.
I have been doing the parks here for the last eighteen months and seem to be the only one at it, I think the others got a bit disillusioned when the banned hole digging, but there is still plenty to be found using the pointy screwdriver
I hope this helps....Regards...Boony