No Cap'n, just that even in Canada, there's only a finite amount of space to store used military hardware while it goes fully obsolete. If you dump it underwater, it frees up room on land & makes it pretty damned awkward, but not impossible to do the type of snooping I alluded to in my earlier post. What it does virtually eliminate is the possibility of the opposition, or potential opposition buying up select parts, or whole sections of your former naval pride at scrap value on the open market.
Folks could still remove those self same sections from your pride & joy, but being on the ocean floor, even in relatively shallow water complicates this procedure enormously & makes it helluva noticeable.....
A more subtle point on the metallurgy side is that even in solid metal, components can preferentially leach out of the metal & into solution, and potentially more importantly, vice versa, especially where salt solutions are concerned. So the longer that an alloy has been immersed in sea water, the more uncertain you are about what may or may not be a trace alloying element which adds to the confusion of anyone who salvages a sample of metal from, shall we say "an area of interest to them".
.....and ChristiaanJ, "Oh, and what about a photo in seat 4B, with an FA bending over you... "coffee, tea, or me?" all in scuba gear?
Priceless, as they say. " Oh Dear, Oh Dear, Oh Dear........