Personally I don't think it's OK for a player to move balls -- accidentally or with purpose.
Lou Figueroa
I don't have a problem if someone touches a ball and then replaces it. Particularly if there is no obvious advantage from having touched it. If the run is in the spirit of a post to the forum like "Here's my 150 ball run" and a guy brushes a ball with his hand and then catches it and puts it back I don't think it matters. That kind of foul is more a technicality that has no bearing on the actual run. I remember one run just like that in this forum awhile back.
Of course if the run were for money the rules obviously would have to cover this up front. Now, if the guy touches a ball every rack that's another matter to me. Don't know why but it just doesn't seem right.