I didn't illustrate well how the two were right up on the bike stand, standing across from each other inches from the two locked bikes on either sides. It seemed like unnatural positioning, especially since the stand is right up against the row of parked cars and one side has maybe two feet of clearance from sidewalk shrubbery. Not how I'd look to admire a bike, though I do believe they were knowledgeable enough to find mine interesting. I wonder if that positioning is some commonly used tactic for shielding what they're doing from onlookers. I don't know how often a bike theft is a result of a lone thief vs a coordinated effort.
But yeah, maybe they were just having a conversation, and the Trek was the once-upon-a-Yeti-owner's.
There are many homeless/impoverished folks hanging around my neighborhood and the library in particular. There's a park and a church with homeless services at the same corner, plus another homeless service center a block away. There's Seattle hipster disheveled, and then there's homeless disheveled, and it's fairly easy to tell the two apart. Anyway, the vast majority of the homeless keep to themselves, and I don't think they cause any significant uptick in property crime, so the bike incident is a bit out of the ordinary.