You've been miss-reading this all along. You can, in fact, snorkel with your Speedmaster. Here's @JwRosenthal showing you how to do it without any risk to your watch. You can relax now...
See, I like an SUV that can handle racing, even though I don’t race it. I also like a chrono that can handle 50m depth, even though I neither dive nor snorkel. I’m a mixed up kinda guy...
I’m prepared to go through this with you, my man-cave is stocked... (only one corner, but it’ll do for a few more pages in this thread!) SNORKEL!!!!
This is covered in Work Instruction 22, where it states: "All OMEGA watches must be tested with the air tests after every opening and closing of the case." The specific testing requirement is dependent on a few things, such as the crystal material, crystal diameter, case material in some instances (ceramic), and what the depth rating of the watch is. The Speedmaster Pro variants are tested using a dry testing machine, like the one shown in this thread: https://omegaforums.net/threads/pressure-testing-a-watchco-sm300.45375/ Any watch rated for more than 10 bar (100m) is required to have a wet test, also shown in that thread. Cheers, Al