Posit basically our current world (focusing for now on the 1st/2nd world nations), but beset by increasing global failures in the technology-based infrastructure: failures of electronics and vehicles are starting to approach the failing faster-than-we-can-fix-them threshold -- and there’s no known option other than repair/replacement. (Assume that the cause is unknown/unbelieved by virtually everyone: magic is returning -- and not quietly....)
Actual food inventories are low and largely privatized. (IMHO worrisome, since this part isn’t exactly fiction, alas.) Food production and distribution becomes strained to the point of unreliability -- resulting in cascading problems in the commodity markets for foodstuffs. But most people in the 1st and 2nd worlds now live in major metropolitan areas, far from where the food is and highly dependent on markets and infrastructure to get food.
The tech failures go from puzzling to serious over a scale of a couple months, and people are frantic! What do they do? Presumably, the urban/suburban people try to get into food producing careers and areas, more and more desperately. At the same time, the rural folks and powers (family farms, agri-businesses, employees and communities) are frightened by the masses of 'urbans' becoming an unsustainable burden on the 'rurals' and try to resist/send them elsewhere.
Assume that conflicting interests have national governments largely tied in knots, other than suppressing large-scale violence. The people are a chaotic mix of distrusting governments and desperate for any help at all. But local governments (states, provinces or counties) -- especially those rich in food resources -- will likely do things to protect their residents and discourage mass arrivals/squatting from outside.
The actual question is in two parts: (1) a move/tactic the urbans could try to get food/arable land and (2), how the food-producers would react. Please give both if you can.
1. What would the urban folks try to do, to get more access to food and arable land?
Example: Urbans travel to and squat on any unused/under-defended land that appears arable (national forests, nature preserves, utility easements) and try to grow food.
2. What will the food-producers do to resist large numbers of hungry, migrating urbans? Example: States require ID of all those incoming at their borders; deporting those without valid proof of in-state residence or other qualification (e.g. ownership of property in the state or similar.)