There are two main reasons why Ruby did this... First was to accent the sheep-dipping of patsy Oswald in order to make him look like a true communist/Castro sympathizer... Second was to look Oswald in the eye and remind him to maintain character in his his role playing as a crazed communist...And that one of the plotters could get right next to him to remind him...
Sure Mark...As if you didn't have to answer how Ruby waltzed right in to the middle of the Press Conference posing as an assistant to Israeli newspapers...The Dallas cops knew who he was...The Dallas cops knew Oswald was CIA...Ruby was instrumental to what was probably a failed plan to kill Oswald at the Texas Theater...They had already killed Tippit...A couple of sweating phone calls and offers Ruby couldn't refuse and he was right at the Police Station making sure Oswald maintained character...Then comes a set-up in the Police Station basement Sunday morning...Somebody should tell Schnapf that Ruby's association with the conspiracy would be a better source for his knowledge of Fair Play than any announcements by DRE...