Although I have the skill to read code and compile it and change it, and sometimes do, it would be a lie to say that I do that for all the software I use. Nobody could practically do that. So then of course trust is involved and the question is where do you place that trust. For me, I want to for example browse who the developers are, look at the code base and where it came from, how actively maintained it is, and look at the community supporting and using it. I think any non developer can do that, and knowing that other people with technical knowledge are also doing that, adds to my confidence that it is software I would be willing to use.