Yeah I wouldn't bring up the bike until I was already there, and even then I'd just ride it and not say anything. Once they've hired you, they'll be a little chickin***t to confront you right away, and give you enough time to show that you'll be dependable (assuming you would be). The situation I would bring up the bike for is if they mention something like: we have a race team or our company get's xxx dollars from the county for each non car commuter.
Regarding discrimination: I don't think this counts, my understanding is that companies are allowed to run credit checks on potential employees (with your permission). Essentially Race, Relegion, sex, and age (and in some states sexual orientation) are the only things they have to be careful with.