Change of tact it is much better, I think you were trying to be helpful but really people will find things out on their own and warning people sometimes makes them seek exactly what you are telling them not to.
As others have said Kriya is just a grouping of certain methods. True methods do not rely on belief or faith they work because they work and you are quit correct about them occuring on their own during meditation.
In the past many of the techniques I have learned did happen on their own and still do, but I will say being instructed helps quite a bit.
Omshanti please consider obtaining initiation trough Kriya Yoga International. I assure you the kriya pranayama is much different than what others teach. They have a very nice group of methods that are well integrated and makea nice harmoneous whole.
Most of them you know, some are really not needed but overall it is very good.
No I am not saying buy the whole story unless you like it, and for heavens sake I am not saying go guru shopping I am certain you are done with that. I say give it a try you might find some good in it, I know I did.
I would not consider anyone a Guru unless they could pass the test. I have yet to meet anyone that can enter the breathless state for prolonged periods of time nor impart a Samadhi to another.
As far as what Lahiri Mahasaya taught originally who knows, I do suspect he taught what a student needed in person rather than a formula, I also suspect no one living is really teaching what he taught becase of this and human nature to change and attempt to improve on things.