Even without municipal encouragement people may wish to avoid collateral pigeon feeding. The easiest way is to reduce or stop the drop of seed to the ground, which is what's attracting the pigeons in the first place. Mixed seed and sunflower seed often ends up on the ground as the birds at the feeder push it around to get at the seeds they want. Sunflower hearts, however, have already been shelled, so each is a choice morsel for finches, cardinals, chickadees, titmice and such. Few are dropped.
Some feeders come equipped with seed catchers.
You can also make your own. If your brand of feed doesn't have too much undesirable seed in it, these catchers should be enough to cut off the food supply to the pigeons. If stopping the seed fall is impractical for some reason, you could construct a net or hardware cloth cover above the ground beneath the feeder. This would bar the pigeons from getting to the dropped seed.