Like yourself i have seen lots of posts on this but i dont believe that i have seen an actual failure, of course it will eventually fail if not sorted sometime.
But on the FL2 the belt for the alternator does not drive the water pump or camshaft, so it will not toast the engine, you could pull in safely should it fail ( power steering will not work) - but again of course i would not drive it for miles like this.
Good old LR using TD4 for 2 different engines, just dont ask if the engine is ford/french or BM and if the timing gear is a belt or a chain - Stewart runs for cover....