The arby's here has market fresh salads and sandwiches, all of which contain pecans. When I asked a few years ago, they did nothing at all to avoid cross contamination. Last time I checked they still have the items but I haven't asked since then about whether they do anything to avoid cross contamination now. We just avoid it.
It stinks because one of the towns we go to for the kids' activities has no safe food places at all. Only McDonalds (with Reese's mcflurries), Pizza Hut and Arby's. And we are there at lunchtime so it would be nice for them to have something safe.