You'll find that even Crowley repeatedly warns (or encourages) LHP followers that, once begun, the path cannot be turned from, despite the follower's regrets or misgivings.
Can you point me to where this is said, preferably making the quotations available?
This is from Crowley's Book of Lies (version with O.T.O. commentary from 1962):
(part 18 on page 36)
"O thou that settest out on The Path, false is the Phantom that thou seekest. When thou hast it thou shalt know all bitterness, thy teeth fixed in the Sodom-Apple.
Thus hast thou been lured along That Path, whose terror else had driven thee far away.
O thou that stridest upon the middle of The Path, no phantoms mock thee. For the stride's sake thou stridest.
Thus art thou lured along That Path, whose fascination else had driven thee far away.
O thou that drawest toward the End of The Path, effort is no more. Faster and faster dost thou fall; thy weariness is changed in Ineffable Rest.
For there is no Thou upon That Path: thou hast become The Way."
Later in part 32 (page 74) he says the same thing, but without the context of LHP. This observation applies more universally.
"Consciousness is a symptom of disease.
All that moves well moves without will.
All skillfulness, all strain, all intention is contrary to ease.
Practice a thousand times, and it becomes difficult; a thousand thousand times, and it becomes easy; a thousand thousand times a thousand thousand, and it is no longer Thou that doeth it, but It that doeth itself through thee. Not until then is that which is done well done.
Thus spoke FRATER PERDURABO as he leapt from rock to rock of the moraine without ever casting his eyes upon the ground."
This to say that once an individual begins down his fated path, he will eventually become that which he practices. In O9A terms, this is when the a-causal is merged with and given presence in the causal and, despite the individual's will (or what Crowley calls "Thou"), the Act practices itself through the individual, rather than the individual practicing the Act.