Six Flags Great America and its Hurricane Harbor water park are bringing back their chaperone policy a week after shots were fired in the Great America parking lot.

According to the policy, all guests 15 and younger must be with a parent, guardian or adult chaperone 21 or older to enter the park starting at 4 p.m. Six Flags noted, though, that it may start the requirement earlier than for 4 p.m. on occasion.

Six Flags St. Louis will reinstitute its chaperone policy this Thursday as part of a nationwide implementation at all theme parks under the Six Flags banner.