I'm a govt employee too, and yes I would. I have a messenger bag that's just big enough to stash a pair of capris and a light shirt. And if I push it, a pair of sandals. I'd probably choose to wear a bike short liner under some nice capris and carry a shirt to slip into once I arrived, that way I'd have plenty of room in the bag for sandals. And I'd lock my helmet to the bike. Chances are most of my co-workers wouldn't know I biked to the event, and those that figured it out would approve.