Not really, especiallly if it is on the trigger before you have decided to shoot.Finger on the trigger is one thing...finger on the trigger and taking up slack is another.
Discipline is not putting your finger on the trigger until you have decided to shoot.That isnt discipline in my book...
It is no more inherently dangerous than putting your finger on the trigger. What is an accident waiting to happen is putting your finger on the trigger before you've decided to fire.that is an accident still waiting to happen.
Don't take it out of context and try to make it something that it isn't. If you aren't comfortable using that technique then don't. The key point is when you put your finger on the trigger, not whether you prep it or not.