What is trust? Trust, to me, is inseparable from knowledge. Part of trust is a confidence that a person will behave as they have behaved before. Trust can also be choosing to have faith that a person will behave as they have promised or as they ought.
When I speak of trust in a speaker or author, I mean a belief that they would not knowingly mislead me, and are honest with themselves and others. The closer our paradigms for evaluating information and making decisions are, the more likely that we will generally come to the same conclusions and the less imperative I feel it to fact-check and substantiate every word.
On the other hand, questioning, testing, independent thought and study, and gracious dissent are not negative. If truth cannot stand up to questions, it deserves to be questioned all the more. Much good has come from questioning taught dogmas, setting out to substantiate or disprove what we believe, and pushing back against long-held traditions that are contrary to reason and scripture.
No person, seminary professor, no teacher, pastor, counselor, or mentor should be above questioning or disagreement. Professors and teachers may have more technical knowledge than we do, particularly about a specialized subject, but this does not necessarily make them more capable of discerning truth, understanding theology, or knowing the heart of God than we are. Our spiritual selves are our own responsibility, and guarding against error is important, no matter what the influence in question is.
Being able to trust those we look up to and learn from is a good and beautiful thing; however, trusting to the point of blind acceptance or even extreme prejudice is not healthy. I sometimes see Christians who identify as progressive, emergent, post-evangelical, et c. doing a great job at questioning and digging into their more conservative influences but neglecting to do the same diligence with the work and message of liberal, progressive Christian influences. Admittedly, they may have more in common with these influences, and thus may be far more willing to take what they say at face value. This is a dangerous proposition, however, because error and fallibility are ever-present with all of us. No degree, credentials, or history should make a person or idea impossible to expose to questioning and dissent. Any person or system which opposes gracious questioning or dissent should be of particular concern- when I encounter such people and systems, red flags raise immediately in my mind. I may end up agreeing with the core idea presented (it generally doesn't happen, but it's possible- I've seen very good ideas defended very badly) or I may not, but I always wonder, when I see a reluctance to be questioned, what fear underlies such reluctance and why, if the ideas in question are accurate and healthy, such a fear would be present. Don't let anyone tell you that questioning a doctrine, teacher, or message is a sign of a weak faith. It isn't. In fact, you may have a weak faith if you treat it like a sugar sculpture which breaks apart at the slightest touch. Strong faith isn't afraid of new opinions, old opinions, or information of any sort, because it truly believes. Weak faith depends on a hothouse to survive, and is worth little. The Bible teaches us to be discerning; "wise as serpents but gentle as doves." Discernment, in my opinion, is predicated on the ability and volition to think for ourselves.
I also wonder, when teachers resolutely refuse to disseminate a concrete, evaluative judgement, whether they are really desiring to encourage independent study or simply giving themselves an out from possible debate of a weak position. To be fair, I've seen both, or at least a genuine intent (as far as I can tell) for the first and the overt implementation of the second. While I would not write off a teacher who thus eschewed objective positions, such tactics do make me want to substantiate the claims and assumptions surrounding the teaching.
Let's do our best to thoroughly vet and inspect any doctrine, dogma, or system of belief or practice that we allow into our lives, no matter where it comes from. A deliberate, robust, personally familiar foundation of thoroughly vetted ideas cannot fail to be a positive force. We are responsible before God for our own beliefs, thoughts, and actions, and trusting others to the point of abdicating that responsibility is both wrong and dangerous. Trust is good; absolute, unquestioning trust is absolutely bad. Independent thought is not evil, and knowing God, God's will, God's nature, and God's story for ourselves is a beautiful thing. So- let's take responsibility for our beliefs, and refuse to be so many sheep led around by anyone who is approved by the church, or sounds edgy and fresh, or is all the rage in our doctrinal tradition. Popular theologies and teachers come and go, but our relationship with God and our spiritual health is here for the rest of our lives. No one can tend that garden but we ourselves. Let's not neglect it.