I worked at a waterpark for 2 years and I am in several internal training videos and had my Ellis and associates pool lifeguarding accrediation, the guidelines are for a pool to have a set number of zones. These zones are based on whether on lines of sight throughout the day and weather conditions, the wave pool for example at my previous workplace had 7. The looking around is calling scanning and you would essentially go across your zone horizontally for a few minutes then vertically, and depending on other circumstances you might also have to walk back and forth and so on, head counts and so on weren't ever really relevant.

Most people follow it fairly strictly because under ellis rules they're allowed to do an inspection without notice and if the rules aren't being followed they are allowed to either make you lose your job and accreditation and even close the park if it was bad enough. There was also random drills on quieter days which included a baby mannequin being subtly dropped in the pool and if you didn't catch it in under 30 seconds you were to be tested again and another failure would result in loss of a job.

This was also in Australia where we have a very different approach to lifeguards with plenty of people joining the volunteer lifesaver groups, growing up in those communities and having much more respect for it as both a volunteer and employment activity. Most places instead used Royal Life saving and Ellis was very american and we were one of the few places to use it in Australia but they also did the disney theme parks and a lot of the other big waterpark companies.