Live on a small rural street where we are all quite close with neighbours.
At the end of the street is a farm, they don't use one of the fields closest to the road so a long long time ago they turned it into a 'dog walking' field for the people on the street (and whoever really).
There is a public footpath through the field which is clearly marked and runs up the side near the wall and then through the other fields. You have to enter this field from the road and there is a big sign which says 'X STREET DOG WALKING FIELD' and a message about picking up after them etc...
It's nice, the dogs often play on there together and we all have a chat if we happen to be on at the same time etc...
However since this warm weather I've seen about 3/4 families all sat down on the field on blankets having picnics. Not with their own dogs, just them.
It means none of us feel we can let our dogs off to run around and play.
One neighbour did point out the sign and said it may not be the best place for a picnic but was ignored.
WIBU to just let my dog off his lead anyway? He does have good recall but I obviously can't guarantee his frisbee isn't going to land in someone's 'picnic area' whilst we play fetch! 
There's not many places dogs can just have a run off lead round here that are closed off and safe. There is a park where people can have picnics literally 5 minutes away!
Its really annoying me. I don't take him to the park because I don't want to get in people's way when they are trying to sit/eat/kids playing etc.. this is the one area that is supposed to be for dogs to run about off lead and I feel like I can't even let him off here now either.