I have waited until Post #24 to offer a different perspective.
We travel by air, usually making multiple connections- a whole lot throughout the year.
If you are making a single-legged journey, you might be more inclined to haul a lot of weight with you. If you face wearing your carry-on bags through multiple plane changes, the lure of carrying them along dulls quite a bit.
Obviously, you're going to do what you have pre-decided to do, but....
1)
They'll steal it for sure! Not much of anything gets stolen out of checked bags, and regulators with their gangly hoses are simply not high on anyone's list. Very difficult to smuggle out of a secured area, and relatively poor re-sale value. Play-it-Again doesn't even want them. What has value to you, at least in this case, has no value to perspective thieves. This is an urban myth that there is rampant theft- just aint happening.
2)
Computers will lock you out if you leave them in unpressurized checked baggage! Not true, but don't baggage check a computer- not because it is going to get damaged, but because
unlike a reg set, it does have a high value for resale, and it's easy to conceal.
3)
Regulators must be carried because they are delicate creatures. 
You are sadly mistaken. You can do anything to them including pound nails. They'll come through it fine.
4)
I pack my camera gear in a Pelican case and always carry it on. Good idea to carry cameras as cabin luggage, but
what is the logic behind using a Pelican case? They're okay for day trip boats, but for a week-long resort based stay? Really? That thing takes up huge amounts of room for what you can put inside it, and it's very heavy. Pad your gear with t-shirts and carry it in a backpack.
5)
My luggage will get lost! Not if you tag it correctly, not likely at all. Do it three times per bag. It always comes through. Like this:
6)
My TSA Locks always disappear! You're always saying how dumb the TSA is- here's your chance to be a bit smarter than them:
Dragging your regs with you, on your person or cabin baggage might save you a few dollars in luggage weight charges, but as soon as everybody follows Spirit Airlines and
starts charging for cabin baggage, I bet these numerous similar threads will reverse-out and everyone will be wondering about how to check their precious, delicate regulators.
Bopping to Coz is one thing, but when you really break away and start traveling to distant exotic SCUBA locales, carrying anything as cabin baggage will strike you as a really bad idea.
