I read the github thread and I get what you're saying CM. I also understand the potential use cases, as @abit outlined, as well.
And while adding that feature to the user-interface may certainly give it more exposure to potential "bad actors", it could also provide greater awareness for a feature that is already available on bitshares (and readily accessible to those savvy enough to use it).
That said, I think the "feature" definitely warrants greater disclosure to clarify and highlight the differences between regular UIAs, and ones backed by another UIA, as was also discussed in the github thread.
Perhaps showing something to the effect of "UIA collateralized UIA" (with a little circle showing "what does this mean?" and a hint window further explaining it, along with the additional inherent risks) when pulling up the asset for trading, and on the asset description page, could go a long way to further clarify the additional risks such tokens may represent.