Because danny, it is a legally required record of your actual experience. Unlike this website where almost anybody can write any nonsense and live out their fantasies (in a few cases), the logbook is a record of what a person has actually done. It is not something to be fraudulantly altered for the purpose of procuring a licence or employment. Neither is it a case of of not being caught out. You might be able to rob your local off licence (liquor store) without being caught out, but that does not make it a target, achievment or challenge for the vast majority of people.
How happy would you be if the surgeon operating on you or your family had sort of lied about his experience a bit. In the event of him damaging you or your family would you say "oh well there you go". I doubt it, and no doubt the subsequent claim would fall squarely on the shoulders of the "negligent" hospital who failed to ensure adequate checks were made. If you see my point !
This is a difficult profession to get in to, and the temptation to apply illegal shortcuts is certainly there. However that does not mitigate or justify criminal actions to achieve a deceptive result. Anyone that does take this route assumes the same risk as the robber in the off license.