The jam and the type of bass are irrelevant. The moment someone steps into the room with me, or appears on screen, we are there for the purpose of learning.
As an educator I have to often find the source of the problem which is at times so far removed from the breaking point that the student had no idea. That's why we are working together. That's why I encourage lessons over video lesson sites, you get someone focused on you and your playing. If they are worth their salt they are able to break things down and present information in an engaging and accessible way to whoever they are working worth. So unless I was at the jam session and listening to it there is no way I can reliably diagnose the problem and the student may be bias about their own playing either positively or negatively.
I'll ask why they are wanting lessons and the long term goal. My job is to help build a knowledge base that people can draw on and manipulate in any musical situation they find themselves in.
I have one question I ask every single student on lesson 1. I have my reasons for asking it and the answer changes for each student, but there is a correct answer. The reason I ask it isn't to make the student feel inferior or insignificant, it's to break down their own barriers and preconceptions so that we can work on getting better together.
What that question is I'm not going to say, I save that for those with the curiosity and desire to truly learn enough to come study with me but in all the years I've taught nobody has once got the answer correct!