I believe that we, ourselves, create this scenario as a supposed "problem" by qualifying and quantifying the requisites that we believe have to be exhibited (or at least "exist) in a person before God accepts them as a bona fide "Christian." We do this almost every time we say the word, "Christian." We add the term a "true" or "real" Christian.........as though there is a "degree" we must work toward and earn before getting our genuine Christian Badge.
My bigger question would be: What criteria do we humans use to determine whether or not any particular person is a "true" or "real" Christian, in the first place?
But, in answer to the original question, "Yes", I believe the Bible constantly and consistently warns us against throwing it all away, even after we have labored so long "in Christ." The passage so many like to quote says we cannot be snatched out of his hand (by an evil force desiring to remove us), but it does NOT seem to ever say we can't JUMP SHIP of our own volition.