<Insert comment by European members about how primitive USA mobile phone technology is compared to Europe.>
Despite my wise-a$$ comment above, in this particular case I'd agree with it. We barely have workable inter-provider SMS here, and lots of phones do not have really good bit-mapped screens of sufficient resolution, and most importantly, sufficient outdoor brightness, to make the barcode work. Especially all the inexpensive color-screen phones which are darn near unreadable in sunlight. I'd trust my old Nokia 6310i (tri-band GSM, bright monochrome screen) over any of my newer phones for this, but I don't think it has the resolution.
Oh yeah, and northeasterner has a really good point - especially since even resorts in N.Amer with good cell coverage have dead spots all over. Nothing sucks a battery down faster than the combination of freezing cold weather with searching for service in a no-signal area.
This sounds like a solution in search of a problem (or in search of VC funding).