I think it's also worth noting in this "Non-Aikido Martial Tradition" forum that there's different levels and layers of teacher/student relationship. Sometime the teacher demands that the student submit themselves wholly to what the teacher is doing and requires that the student blindly follow. One could argue that is something of a traditional approach. There's also perhaps a more modern approach that some martial studies (and IS as a discrete skillset) are more based on examining them as tradecraft (which can require an apprenticeship similar to the above scenario - or a more casual, let's get together and talk shop, even when one amongst the group is a more senior practitioner doing most of the sharing). Then there's sports-based athlete/coach relationships . . then there's every hybrid and in-between version you can imagine.
In either case, I suspect, you would want to be sure that someone in whom you've placed your trust and well-being, is going to treat that appropriately and with regard. Question is - what are your standards for assessing if someone is going to appropriately handle the trust you give them when you set out to learn something they have to teach?
Personally, I am always wary when I first meet someone and I play ball with what they're doing, trying my best not to let what I think or think I know get in the way of what they want to show me. But I am also guarded and if I decide that they're going to try to hurt me intentionally, it's game on and I respond accordingly. Deducing whether someone is a stinky noodle, however, I don't claim to be able to determine easily, because I've had perfectly charming teachers demonstrate seemingly sociopathic tendencies in varying degrees . . so it gets to be a crap shoot, either way.
Now, factor in trying to determine the quality of goods they have for sale (to use a crude term) - and you've got additional layers of complexity. Whether it's a koryu with a guarded gate or an MMA gym where all you have to do is show up - the culture and content you're only going to get exposure to by stepping through the entryway and getting stinky (to use another crude term)