It might have been more interesting to show JR looking for the son that Kristen claimed she had and then found out Christopher was his son. If they had shown JR look worried about where his son was and wonder why he couldn't find him. I wonder how Pam would have handled it if instead of offering to let Bobby raise his son in exchange for voting his way, if JR had just shown a genuine desire to find and raise his own son. It would have been a dramatic moment when Pam found out Bobby had lied to her and had tried to take JR's son and pass him off as a baby he had managed to adopt from a lawyer. Finding out that Christopher wasn't theirs, that he belonged to JR and Bobby had tried to hide all of that would have created a very tense situation. Having to give Christopher to JR would have been difficult for Pam. She likely would have blamed Bobby for lying about the whole situation and allowing her to get attached to Christopher instead of telling her right away: "No, this isn't a baby I brought home for us; this is JR and Kristen's baby." Bobby repeatedly said the two things he hated most were lies and secrecy. It would have made him look like a complete fool to have been saying that all those years only to expose himself as a total hypocrite.