I’m happy to perpetuate the myth. I stopped using 5200 because it was more work at no advantage to me. The difference with 5200 is it is both a sealant and an adhesive, a strong one on clean surfaces. You don’t need an adhesive at all when bedding as you have a mechanical system of holding the pieces together, just need a sealant. I have also removed pieces with 5200 and you certainly can get them apart with enough effort, and there are softeners out there that work in 20 minutes to an hour pretty reliably and I have used those too. But why? It takes more time with little benefit. Through hulls and the like don’t generally come apart. I can rebed a thru hull or replace a seacock in 15 minutes start to finish with a good sealant, not so if I have to work it back and forth and then maybe sand a bit to get the 5200 clean off. Maybe only another ten minutes, but ten minutes with no benefit. Anyway, I stopped using it because I don’t like wrestling with it.
3m 101 was my favorite sealant until they stopped making it. Cured under water. Stayed flexible for at least a decade or two. It was polysulfide and now lifecaulk is the one hold out that makes a good polysulfide based sealant. I liked 3m 101 better, but they are very similar. I find the lifecaulk messyer for reasons I can’t explain, something in the consistency. I also have largely went to butyl tape for most bedding. Stays flexible, fast to use and no cleanup. The polyurethanes are rather awesome products today. They also stay flexible and you essentially choose your preferred amount of adhesive property, 5200 being the most tenacious. 3m went all eurethane because they can make any variant on the same line with minor tuning of the chemistry. Too expensive to make 101 for too little differentiation. Truly hard to go wrong with bedding products these days, almost everything stays flexible for at least a decade now. If you have an application wher the adhesive properties are useful or the mechanical means is subject to failure risk, then 5200 is your best choice. I see zero benefit to deck plates, most Stanton’s, thru hulls, etc. I’d I had a mitre joint with a hatch that has thin frame and lots of leverage I’d use 5200 on that all day long. Same as a windlass that gets torqued around a lot, 5200. Everything else, no way. I want to encourage future me to not ignore a bedding risk. Past me spent too much time wrestling with 5200 after I went through my own 5200 for everything phase. The one thing I wanted 5200 to stick to was the bottom of an aluminum tank to some plastic spacers to ensure air flow. Was not permanent, but lasted long enough to sit things down. Some things even 5200 won’t stick to.
Our favourite adventures include Desolation Sound Marine Park (north of Powell River) which is virtually in our "backyard", and we are looking forward to exploring the Broughtons. 
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