I'm going to preface this by saying that I think virtually all clubs would love to be able to cook the books and that I dare say most of the major clubs have at one time or another floated ideas that may not have broken any rules but gone against the spirit of the game.
Abu Dhabi, Paris St.Qatar and others (I'm thinking a lot of the Chinese investors may get more leeway from the Chinese government but accept I might be wrong) get away with what they do because they face absolutely no repercussions for their actions. If we tried what they have (allegedly..ahem) done then it's not just LFC that it seriously effects. It then goes through FSG and into other businesses owned by them. If Spurs tried it, it effects Enic and ultimately Joe Lewis's other business. Same with the Glazers, especially since United are listed on the NYSE and subject to their rules. What are Abu Dhabi going to do, punish themselves and tell themselves they've been bad?
The only true punishment they can face is sporting ones and that's ultimately stripping them of titles and trophies won. I suppose that opens them up to legal proceedings from other clubs since in theory they might not have legitimately qualified for the Champions League and all that money gained could have went to say Arsenal who missed out.