The fries at McD here are always done in a separate fryer so they don't share grease or anything with other things containing gluten.
Given the problems I've had with their fries... I just figured most mcD's do not care about contamination issues (or just aren't aware). I'd love to be able to eat some fries on the road once in awhile. And I wish that there was a good way to convince mcD's to make this 'seperate fryer' idea the RULE rather than the EXCEPTION.