The narrow Intracoastal Waterway channel can become very crowded on weekends. This photo shows boats three-across coming up from behind. In the opposite direction, boats are traveling two-across. The photos do not do the situation justice... these boats are closer than they appear.
Trying to keep an eye on what is behind you, what is to the side and what is ahead can be a challenge. It's not uncommon to simultaneously have a dozen boats moving behind you, another dozen coming at you and 2-3 trying to pass you.
Many boats do not "stay on their side." Many times a boat will approach you head-on (traveling on the wrong side of the channel.) In this case it's best to maintain a definitive and predictable course for your boat. Generally the other boat will correct its course. If both boats are trying to course correct it becomes a strange dance! Pick a direction and stick to it. Of course leave enough room for an emergency evasive maneuver if needed.
In the course of this half-mile, a half-dozen boats are in front of you and a half-dozen are coming toward you. Another three boats are immediately behind you and three are alongside.
There is strong tidal current and wakes... just to make things more interesting.
16 moving boats are between you and inlet (a distance of about a mile.)
Boat traffic is worst on the ICW from Peanut Island north to Hobe Sound. Traffic moderates somewhat north of Hobe Sound.