I have ridden a Motorcycle and have been licensed to do so for 35 years. On my 70's sportbike it was possible to ride with a kilt and I have done it. My current bike is a cruiser style and it doesn't lend itself well for tucking my kilt in.
I always ride wearing gloves no matter what the weather. sturdy footwear. Almost always ride wearing long pants or riding gear.
It's the short hauls near home that seem to be where one is most prone to an incident that is not condusive to ones health.
Basically don't do anything or wear anything that may distract you from the task at hand....meaning make sure you are safe! Watch out for the other person. Always look for an escape.
If you choose to wear a kilt, try it out in a safe environment first.