I'm not sure if it applies, but look at how I handled looking at inspect target's items in my addon. Far as I can see, it does not cause taint.

https://github.com/Ketrel/BetterItemPreview/blob/master/BetterItemPreview/core.lua

Hi,

Thank you for the feedback, but your addon will also taint, as will any addon that overrides HandleModifiedItemClick. If you reload UI, inspect someone and Ctrl-click one of their items (without first explicitly opening the dressing room), the dressing room will be tainted, and you will not be able to Link Outfit -> Copy to Clipboard.

You are right, I've never used that feature and didn't notice it.
(Though I can still perform the function with mine, I get the taint error, but it still works, possibly because I call the original function? Though after that, I need to reload for any further loads)

Do you mean you actually get the outfit copied to the clipboard? What happens to me is a message is printed saying it got copied, but actually did not.

I've since updated my addon and it no longer causes taint due to it using hooksecurefunc to hook rather than replace HandleModifiedItemClick.

I'm guessing this method would work for mogit as well.