Yeah they sure do Harry, I've got about 10 sites around here I do regularly, some I do say twice a year and usually get between 50 and 100 bucks each visit. Wish gold detecting was the same too.
The site I did yesterday is huge, maybe 50 acres of sportfields, I have pulled hundreds of silver coins from this place, about 50 silver rings and I think 4 gold rings plus a few grand in goldies. As soon as I feel I've finished with the site I go back and start finding more stuff. It replenishes quickly with moderns as winter sports will have 1000 or more people every weekend there plus the kids school sports.
Also here on the Northern Beaches of Sydney we have some of the busiest beaches in Aus over summer, they can be profitable too. We have quite a few old parks also that have or did have plenty of silver coins, I couldn't believe how many to be honest, they are thinning right out now as I've been hitting them hard. Still pockets of them though that I've missed.