only carry on, never check in unless the film has been developed. once you check in, the scanners are very high intensity and you will instantly ruin your film (get zig zag lines on the negs).
The hand carry scanners are film safe, they even have a sticker on the machine saying 'film safe'. I brought 10 rolls to Thailand and Japan each last year, no problems. Film rated between 200-800 and scanned about 4 times hand carry, didn'nt notice any hazing or other probs.