We SUPPOSEDLY have Rita offering the nannies money. As far as I can see...It wasn't to change their story, it was to seek the affidavit which confirmed their "first story". I'm trying to see what the "guilt" is in this case. IT's not witness tempering as far as I can see....if there is/was an affidavit to start with. Bain admits they set Rita up.
I think all that Bain was trying to do was find out (for Howard) who Rita's other source is.