I have had more confrontations on pool decks than I've had as a cyclist with drivers on the road. Why? Because so many "swimmers" don't bother to learn 'lap swimming etiquette.' I found this Guide to Lap Swimming Etiquette that some of you may find helpful. I've liberally borrowed - and shortened - a few that may need to be shared as a sort of Top 10 list:
1. A swimmer entering a lane being ‘split’ by two people (each swimming up/back on their own side) should be sure before s/he begins to swim that s/he alerts both individuals to the need to change to a ‘circle’ format (everyone swimming counterclockwise on the right side of the lane). Note: I'm not sure everyone who posts here knows that it is acceptable to split lanes with as many as five or six people.
2. Swimmers resting or otherwise waiting at the wall should stay far to one side of the lane.
3. Swimmers arriving at a pool should do three things before getting in the water: Make note of “Fast, Medium, and Slow” lane designations. Spend a few minutes observing and roughly timing the per-lap pace of swimmers already in the pool. Select a lane containing swimmers moving as closely as possible to the pace that one realistically expects to swim throughout his or her entire workout.
4. An overtaking swimmer should gently but distinctly touch the feet of the swimmer being overtaken.
5. Swimmers being overtaken should never stop in the middle of the pool, nor should they continue beyond the next wall.
6. Swimmers being overtaken should not attempt to speed up (or slow down) once ‘tagged’.
7. A lead swimmer who feels a touch on the feet from an overtaking swimmer, should continue to the next wall, then stop in the corner of the lane to let faster swimmer(s) past.
8. Swimmers enjoying a draft behind a strong lead swimmer, but who are just barely able to hold that pace should think twice before tagging the leader's toes and requesting to move ahead.
9. Overtaking swimmers should not attempt to swim ‘wide’ past a slower swimmer.
10. Be aware of how ‘wide’ stroke mechanics may impact adjacent swimmers.