Welcome Subcolour.
I've used a fair bit of old print film over the years and the odd expired slide film and all I can say is that I doubt the colour will be faithful even if it isn't scanned. Therefore, scanning seems unlikely to make much more difference. The baggage hold x-ray scanner is a different kettle of fish to the carry-on x-ray scanner so, if it were me, I's just go for it and hope for the best. Ultimately, is what you're likely to be photographing a serious piece of work? If so, I wouldn't be risking 12 year expired slide film whether x-rayed or not.
Incidentally, don't forget to introduce yourself on the Meet the Filmwasters thread on the Forum. there's also a load of great collaboration galleries (not sure if these are up and running just yet) and podcasts to have a look at as well. I'm sure you'll have a great time here.