No. That doesn't seem like a reasonable environment to start a conversation. There's is an art to it...
Basically, if you want to start a conversation with a stranger then I'd recommend doing it in a place where they can 'escape' from you. If you corner them, say on the tube, then they have no means of leaving and hence they will feel as if your approach is hostile. And that's especially true if you are both sitting or face to face.
I recommend reading Strauss' book because it's fascinating, but the bottom line is approach people from an angle (not head on and not from behind). Make sure they've got the physical space to leave if they want to, maintain enough distance that you are not in their personal space, and if you do get chatting it can be helpful to indicate in some way that you are only temporarily there talking to them.
I really like your qualifications. In my own experience, e.g. with regard to "networking" advice that is promulgated, they are too often ignored. No wonder the advice feels awkward to someone who is sensitive to exactly these issues/concerns.
"What I do is ask them some question that they could plausibly answer as a way to starting a conversation" - there is an idea right there - how to move from an opener to a proper conversation in a non-pub/bar/club environment ?
Basically, if you want to start a conversation with a stranger then I'd recommend doing it in a place where they can 'escape' from you. If you corner them, say on the tube, then they have no means of leaving and hence they will feel as if your approach is hostile. And that's especially true if you are both sitting or face to face.
I recommend reading Strauss' book because it's fascinating, but the bottom line is approach people from an angle (not head on and not from behind). Make sure they've got the physical space to leave if they want to, maintain enough distance that you are not in their personal space, and if you do get chatting it can be helpful to indicate in some way that you are only temporarily there talking to them.