I have been on the receiving end of full LP losses not because of me deciding not to join the match, not because of me choosing to quit a match, not because of my internet service provider, not because of power outages on my end (although that did happen to me ONE time), but because the client failed to launch after champion select. It is an uncommon occurrence, but one that has happened to me at least half a dozen times.
When this happens, the only way to force the client to launch is to end the LoL client through the task manager then reconnect through the launcher and hope that you load in time to avoid a remake.
This is not the fault of the players, they do not deserve full LP losses over a broken client.
Fix your client, Riot. Until then, stop stealing our LP!