Which is interesting because there is a brown mug with this exact same design still sitting in the gift shop. Which leads me to think this was more due to cultural issues than copyright.The the design on the tshirt is pretty obviously derived from Oceanic Arts original work.
And as someone else said, it all depends on the contract, but I would be pretty surprised if Oceanic agreed to Disney creating merchandise (a shirt which is sold is not an ad) based off of their art and designs.
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