I know an old lady who swallowed a ladybug....72,000 ladybugs is not harmless. Now the county is going to have to purchase at least 1000 birds to come in and eat the ladybugs. Then they'll have to get 500 cats to come in and eat the birds. Then 250 dogs to chase out the cats. Not to mention the mess all those insects and animals will make.
This is not a harmless prank.