A gameplay mechanic is an action or system. A boss fight isn't a mechanic. It's a level or instance, location or event. No one is altering mechanics when they skip death singer. Altering mechanics is akin to entering a cheat code for unlimited ammo or God mode. You want people to stop abusing checkpoint systems? Get games to be developed without them. Roguelikes don't go over well with the mainstream however... Also, lighten up on the worthless player remarks. The respect given to your point of view drops considerably every time you talk like that, whether it's the status quo of the forum culture or not.