Is that really good advice? Swim to shore in Cozumel? I would think that it might be more practical to inflate the SMB, try to relax and pray that sooner or later the capt will be able to find you down current and down wind. Actively swimming may put the diver much closer to shore than would be expected and might be harder to find. It also will tire the diver out and may make it harder for buddies to stay together, may tend to induce decompression sickness due to the post dive exertion and having to actively swim toward shore may induce panic in some people.
Since I've only dove Cozumel a few times, I am curious if "swimming for it" is good advice for that location.
If I were in a very remote location and feared that the dive boat had been disabled, or forgot me, or sunk or something, I might try to swim for shore, but in a location where there are other resources to perform a search for lost divers, I think I would rather float than swim.