Bridezilla sis wedding is coming up. It should be a train wreck and I'll post all the details for your enjoyment afterwards

I'm Skyping the ceremony and am not sure who will be in charge of me for this, I just know it won't be MOB/FOB. Sis and her FI are getting married at the RD because the officiant (whom they have no relationship with) they booked can't legally marry them. They made this decision months ago and wouldn't consider a new officiant or using two officiants. Although you don't need to say the traditional vows to get married, to be legal the ceremony requires you to verbally confirm who you are, that there are no impediments to your marriage, that you willingly take the other person to be your spouse, and you are pronounced married. We sign the papers during the ceremony here, and I've asked around and no one I know has been to a wedding where they papers aren't signed during the ceremony. I have no idea if they are going to fake signing the papers during the not legal re-do ceremony. I also don't know how many people know and care that they are seeing a non-legal, re-do ceremony. Here is my dilemma: Do I ask the person Skyping me in why they didn't sign the papers during the ceremony? Or is this too petty?
If it changes your answer, she kicked me out of the WP over attire issues (out of my budget and comfort zone, but made attire exceptions for her friends) and she did everything she could to be the centre of attention at my wedding, and tried to ruin my day by accidentally-on-purpose spilling her dinner on my dress.