Question about the Left Hook

I've heard that the Left Hook should not cross your center line when you throw it. Is that true?

More or less certainly not past the Back Foot if its where it should be. Thats where the Drive comes from, the Heal should be in line with the Coxxys yours and everybodys centre of Gravity.

You don't want it to go too far, for otherwise it's as bad as reaching, you're off balance and vulnerable to a counter.