You can pre-rig as many as you want. I bet I still have o-rings on some of my Big Magic Stiks from last year....still in the bag. I don't pre-rig them but I will just toss them back in the bag at the end of the day or when I switch up colors.
Al.....I was thinking about this a bit more....I have had the o-ring pull off some of the senko baits when pan fish bite on. Not very many but it does happen. The ones I had trouble with are the 3X ones....Strike King I think...that they sell at WalMart? They are very stretchy and hold up well but also pull out of the o-rings easier. I don't think I have ever had a Magic Stik or the Black Magic (Gander) brand pull out of the o-ring though.
You don't have to limit this to senko type baits either. If you can fit the bait into your wacky tool then you can "wacky" rig it!
Brian
I have had this happen on just about all my plastics. It was mostly happening because I was trying different orings out to see which ones worked on the different baits.But it seems that the ones that are scented externally do slip more frequent.