It seems from reading here that this is not the case...
Nope, it's not.
I blew out a baffle on one side (4-chamber tubes), and opened a seam on the tube itself (probably in quick succession.) The seam was repaired; didn't feel like tackling the baffle. Might have it repaired when I have OP valves installed (whenever that may be.)
A buddy of mine has blown *all* the baffles on his Zodiac 16.
As an FYI, these both occured during not-so-hot weather here, with night temps in the low 50's or so and daytime temps in the 80's (degrees F). Both boats were situated on trailers in direct sunlight though, so the daytime temps may be a bit misleading.
To the OP: As far as I know, the failure point will probably be a seam (the fabric itself is much stronger than the seams are), so the soapy water thing should help you find it, unless it's buried alongside the hull or something like that.