In case you were wondering....Two weeks ago there were small flags on our playground. We have a sprinkler system, and were having the yard aerated prior to re-seeding in the hope of repopulating grass instead of weeds. The flags were used to mark where the sprinkler heads were located so that the machine they use to aerate the lawn wouldn't damage the sprinkler system. No chemical treatments are used on our lawn. They are also not used on the park behind us; they are using organic treatments to keep the park green.