How do you deal with players not knowing the rules?

Haze wrote:

this is hindsight and all that, but Theft of Vitae should've been printed as "steal blood or life" a long time ago.

it's the only mechanic in the game where blood and life seem to be interchangeable, while every other card that specifies blood only refers to vampire blood.

There's several other cards that steal blood that don't specify 'blood or life', all of which can be used to steal life.

Absorb the Mind at [myt]
Call the Lamprey (at basic this only effects allies)
Diversion at [tha]
Drain Essence
Kraken`s Kiss at [VIC]
Tongue of the Serpent