Don't know where you got this info re botulism?  The purpose of splitting  is so more surface is exposed therefore it cools a lot faster . Bakers should NOT be wrapped in foil> At least not in a classy operation. First when wrapped they do not bake, they steam. They should be washed well ,as like me some people eat the skin. rubbed with oil and sprinkled with salt, both for texture and taste.. Some people bake them on kosher salt . A real baked tater should be fluffy when cut into

Re the  Yukon Gold or any other kind, steam or cook almost all the way thru, put pot under cold running water  let get down to room temp or below,put on a wire rak on top of sheet pan and put in  fridge. Forget plastic bag it is not needed. To reheat just put back in steamer or boiling water.  A good baker should be fluffy on the inside., and should not be all cooked at same time for service  it should be staggered so they dont sit around and get soggy and pasty.  If dinner service is 6 to 10 cook x amount every hour so they are fresh and don;t  sit around for 4 hours.. It's little things like this that make a quality place and good dining experience for the patron.

The botulism threat that occurs with foil wrapped potatoes happens when people put the potatoes away in the refrigerator for the night without unwrapping the potatoes first. The bacteria that causes botulism is naturally occurring in the soil (easy to be on a potato skin) and needs a warm low oxygen environment (wrapped warm in foil overnight) to form the spores that become the toxin that is botulism.

The whole Yukon potato boiled and put in the refrigerator for the night will be fine as long as you don't seal it up in a zip lock bag, merely put it on a shelf in the refrigerator unwrapped and uncut to cool.

How onions and a baked potato became sources of botulism poisoning

by Roger W. Miller  

The other botulism case involving an unlikely suspect, the potato, occurred in Baton Rouge, La., in May of this year. A 37-year-old woman was hospitalized with slurred speech blurred vision and respiratory problems--all signs of botulism. The woman had eaten lunch with a friend at a local restaurant. The friend had not become ill, although the two had exchanged food. What they had not exchanged was the baked potato which, the victim had remarked, was "screwed up."

But the potato was suspect before that remark was learned of. The owner of the restaurant, when contacted by health authorities, explained that he had prepared the potato differently on that day. It seems the two women had come into the restaurant before opening time. They were served nevertheless. The baked potato selected was one that had been left over from the day before. At it had previously been baked in a foil wrapped, the owner merely reheated it before serving. It had remained at room temperature overnight.

Those circumstances seemed right for activation of the botulinum spores. And sure enough, a foil-wrapped baked potato was recovered from the restaurant's garbage and sent to FDA's Dallas district laboratory, where an analysis was positive for type A botulinal toxin, the same type recovered from the victim.

Left out overnight and non refrigerated,  Dont use foil anyway even home. You don't need it.

It would have been fine. I store leftover potatoes in ziplock bags all the time. Let cool to room temp, into the bag and into the fridge.