Two different supermarket cashiers have expressed mild surprise at my willingness to put cold, packaged meat and cold, packaged cheese in the same shopping bag, explaining that other Jewish customers of theirs are careful not to.
Any idea why they might be careful about this (other than simple error)? Is there a basis for this stringency? Do any pos'kim (halachic decisors) recommend or require it — or, for that matter, mention it (with reference to modern shopping practices) as not required?
(SA YD 91:1 seems to almost explicitly permit the practice:
One's allowed to bundle [cold meat and cold cheese] in a single cloth [in such a manner as they're separated —Aruch Hashulchan]: we are not concerned that they may touch one another.
(That's my own translation and omits context and commentary. Certainly don't rely on it for practical halacha.))