There is someone who meets her elderly parents for Shabbat together with her two siblings, who are not religious. Everyone shares the food preparation, and my friend wonders whether she is allowed to eat the food they bring. The food that is being brought is kosher and not cooked on Shabbat, but will be brought in a car on Shabbat or carried through an area without an eruv.
The short answer is, yes, the food may be eaten. In this case, we are dealing with the issue of ma’aseh shabbat when the food was carried without an eruv (or driven), but no melakha was done in the making of the food. In this case, the food is permissible for the following reasons:
1. Nowadays, we can generally assume that people are either tinok she’nishbah or omer mutar, and the Mishnah Berurah (MB OH 318:7) rules that, when necessary, we can rely on the ruling that ma’aseh shabbat does not apply in such cases.
2. If it is carried in a karmilit, there is a question if ma’aseh shabbat applies to d’rabanan violations, and according to Gra, it definitely does not apply if it is not b’meizid (MB OH 318:3)
3. If the melakha did not transform the object – as is the case here where it was only carried and/or driven on Shabbat – then it also is almost definitely not a problem if it is not b’meizid (Beiur Halakha SA OH 318:1 ד”ה אחת)
Follow up question
These are people who used to be religious and driving from city to city so not all of these leniencies apply, however, the third one does. Is that sufficient?
Yes, and to further clarify, while the third point is also said in reference to a case on non-meizid, one of the positions it is based on, who is the Ritva (Chiddushei Ritva Eiruvin 42a), applies it even in a case of meizid, and one can add to that that there are poskim (such as Rav Kook – see Iggerot Ha’Ra’aya, 1:138) who are ready to apply tinok she’nishbah even to cases of someone who grew up frum – which would get back to the first leniency leniency.