My two boys and I were at Wilderness Lodge last year when they were doing some training. We went for a swim in the morning and there were about 20 life guards at the pool. During the drills, there would be a life guard at each station on duty watching guests, life guards participating in the training next to each station, and about 10 in the pool pretending to be guests. After about 15 minutes, a life guard in the pool would slowly sink to the bottom. Once the person was spotted, the instructors would confirm it was part of the drill and the training lifeguards would go into action leaving the on-duty life guards to continue to watch the pool. After the rescue was complete, the did a quick debrief, rotated positions (including on-duty life guards) and 15 minutes later there was another rescue. I was impressed with the training but was surprised the did it with guests in the pool. I guess it added to the real world training since you had to scan the whole pool, not just look for a life guard laying on the bottom.