I think its always best to print the films with reg marks on them.. Some printers use them, some dont. Some register their screens with the films. It doesnt take that long to tape off registration marks on the screens after registering a job. My opinion, as good as anyone is as a printer, registration marks are never a bad thing. Some prints, registration is crucial. Index seps for example, where each square dot buts up next to the others instead of overlapping like traditional half toning, is a type of print i would dread if i didnt have reg marks.