This is a horrible tragedy and should be a huge wake up call for something that should have been implimented years ago. The current at Hol Chan has always been a challenge especially during outgoing tides. I was a dive instructor here for 15 years and dealt with this on a weekly basis. When the current is outgoing and strong a plan has to be made before entering the water. This includes evaluating the guest that you are exposing to these conditions. There is a point during outgoing currents where swimming far into the channel is at best risky. I have always thought that it should be displayed by the "rangers" when the tide is outgoing and how strong it is (maybe some kind of grading system). When the current is medium to strong there should be enforced warnings as to how far groups can venture into the channel. Different colored buoys for example. If the rangers are flying a yellow flag then you shouldn't go beyond the yellow buoy. I hate policing but apparently it's time to start making decisions for people so tragedies like this can be avoided. This is mostly about tides and operators can start planning their dive/snorkel trips accordingly - I alway did. Let's do something with the park fees to keep this kind of horrible occurrence for happening again. There are many ocean current meters on the market and some at very realistic prices. My deep condolences to the families of those that perished.