It depends on when they do the rounding. If they round the final distance number, all you've done is reduced the accuracy to concentric circles like a dartboar

It depends on when they do the rounding. If they round the final distance number, all you've done is reduced the accuracy to concentric circles like a dartboard, and you simply need more samples to regain the precision. If they round the input location to the centroid of some larger region-- a square several kilometers on a side or a map shape for a region-- there's no precise information to be leaked.