I would possibly eat something cold on the dishes, but I would not eat mac n' cheese on DE dishes (even it was made this time with ch"y).
Listen the bottom line is that most people don't hold that Ch'S makes the utensils treif. R' Moshe, although recommending one be
machmir, clearly writes that one who relies on it is not a
m'zalzel b'issurim.
You can speak for yourself but I know countless of people that are
makpid on only eating Ch"Y, and not be
makpid on the utensils. It could be because they assume that the
keilim are
aino ben yomo, or because they only accepted CH"Y as a
chumra. You could disagree all you want but it seems to be a very common practice to not be
makpid on
keilim