How so? We still run it through jQuery.merge on the line below this. The only scenario I can think of where this might (maybe) fail is if we have an input that is both an array-like object (containing nodes) and has a nodeType property and is intended to be interpreted as adding the inner nodes instead of the outer object having the nodeType property. Afaik we don't have that.

Also, regarding the function argument, do you mean because functions have a length property? That is an interesting case indeed, though afaik this doesn't change the behaviour in that case.