I got burned with rolling bars on a Red One M shoot. 23.98 1/48th, shooting 2 passes of a scene to be compt'ed together. In the end we cleaned it up in post, but now I shoot a test, wide lens on a even light surface to verify. If I don't have time to test I shoot at 1/40th or 1/60th. Some cameras appear to be more sensitive vs others. I've never personally experienced rolling bar issues on 3-CDD systems at 23.98 1/48th, but I have had problems with rolling shutter CMOS cameras. However, most of the time it's so subtle that it's not an issue.
Hope this helps.