You are very right to note that realizing a need to do personal investigation is not cause to let our guard all the way down. I’m glad you brought that out.

I do want to be more gracious and not be negative towards “teachers” simply based on their reputation. I think it important to do my own investigation before forming an opinion. It also helps to negate slander before it gets started. Instead of giving someone my opinion, I can tell them to check it out for themselves while fully trusting the Holy Spirit (if they are believers) to guard them from gross and dangerous error.

I think my reaction to such a question (have you read every book of theirs from cover to cover), would be, “you don’t have to read every word somebody has written in order to discern if they are teaching goofy stuff…

There is a danger in just shunning certain authors because we’ve been warned by some other person that they’re no good, but that doesn’t mean we should swing all the way to the other end of the spectrum either…

I think the danger you were zeroing in on is a real one, that once someone starts seeing their books and publications as the real way to “reach people”, then it’s real easy to get sucked into the trap of getting more and more endorsements, because it’s all being done in the name of “reaching people”… IMHO, one is flirting with compromise in such a situation….

If we are to trust the Spirit and the writers of the NT then we have to agree that it is the Spirit who will “guide into all truth”. We are to only teach faithfully as the Lord allows and the responsibility to discern and reject false teaching falls on the individual Christian. We want to play the Holy Spirit in way too many people’s life, I experienced this greatly with my wife.