[quote=FiendishFox]
My vassal is going to have an unfortunate "accident", I think ;)
[/quote]

Then his beloved son inherits. A beloved son who might suspect you of murdering his father.

[quote]And if the plot gets discovered... War of Independence! Man... I want to start playing CK2 again.[/quote]

Who has time for plots? Just twiddle your thumbs for a few years until you have more money than God, then spam the assassinate action.