What's the Deal with T-shirts with Random, Gibberish Japanese Writing on Them?

Just as native English readers are surprised by badly-translated English on t-shirts sold in Asia, so are native Japanese readers astonished by the bad combinations of Japanese characters on t-shirts sold in the West. You might think this is just progressive laziness among clothing designers, but there is a genesis for the story. Simon Whistler of Today I Found Out also tells us the origins of the reverse- Asian t-shirts sporting random English.