Feet without dignity
I'm gonna lie awake tonight giggling about this one. Those first few paragraphs are hilarious and sadly that appears to be right out of Hombu.
I've been exposed to minor bits and pieces of what I think you are talking about. It's very hit and miss in my experience and usually used to displace center not sweep as I'm guessing Judo would probably do it. I've also done a small handful of things which involve standing on uke's foot or hand which appeals to my baser self. I wouldn't attribute any of this to a formal style however. It just seems to come up occasionally.
To tell the truth, I'd completely forgotten all about the foot stuff until you brought it up. Thank you for that as you've given me some ideas and a laugh as well.