Speaking as someone who has spent ~ 90% of my life as an ardent girl watcher, the whole passing worry is a moo point, it's a cows opinion... if you will When I would sit at a caf? or some other girl watching spot, I would continuously scan my surroundings for pretty girls, as I'm genetically predisposed to do. When I would eye someone whom I thought was crossdressing or trans, I'd simply continue scanning, unless they looked so good that they would 'Pass' if you will, in which case I would lock on and scan, and scan. My point is if you're worried about people staring, don't, because almost all the time it will be the unsaid compliment that you likely desire.