people w/ geared bikes

Anyone shift up without using the clutch, any thoughts?

Not recommended. It becomes a safety hazard should it not engage. Plus it can cause serious transmission problems. Fun but not recommended.

I have, although not on a regular basis. It's a useful skill to have in case the clutch goes out (useful in an automotive context, too). I know that in a car the main problem/risk is that the synchronizes can be damaged if the revs aren't matched during the shift - I'm not sure if this is an issue in a motorcycle given a wet clutch/transmission setup.

Upshifting is not a problem. Some racing riders us a "kill" switch momentarily ease off power while shifting. It is much much faster than the clutch. Shifting down can cause a problem if the revs and speed dont match.

That's why I carry a spare clutch cable in the trailer. I changed it when it started to get a little hard to pull, after lubing. (30k miles)
It's easier to change at home with cable in hand than on the side of the road and not have one.
MaxB (your mileage may vary)