Hey Mike sorry I'm just seeing this but I don't think you need to worry about it. My plated xr250r got parked anywhere and everywhere around town, usually with helmet and jacket thrown over it, and I've never had it bothered. I just get you a simple bicycle cable lock that you can loop up on the back of it and then run through the front wheel and frame when you park it somewhere if it's somewhere it's out of sight of general public or you're worried about the area or whatever.
Like I said I've never had someone screw with my bike when parked anywhere here around town. I thought it can't happen but it'd be rare.