When my wheel bearings went bad, there wasn't any wobbling when moving the wheel with the car jacked up...I have heard others say the same. I'm not sure why they didn't, that is a classic sign they are going bad.
Mine developed a high pitched squeal when driving, after starting out as a humming noise, that was the tell-tale sign for me.
If you want to be on the safe side, I would say replace them if you have over 150k miles on the car-especially if you have lowered the car or drive hard.