I think theft from suburban and urban gardens can be a problem, and as we probably have more gardeners than farmers here, that is the more personal issue to us. It is also easy to mistake animal raids for human raids.

But as for humans, that is why I try to plant my small-fruited items or items that don't look like food on the edges of the garden where a casual passerby might see it. Plus, people can be lazy and don't want to spend thirty minutes picking miniature produce whose equivalent weight might be harvested in one minute if full size. Examples--Amaranth does not look like food to most people passing my garden. Little native plums take too much time to pick and if the someone even stops to taste them, they might think they are not for eating (can be both sour and alum-y). I favor small crab apples over snacking apples, partly for that reason. People don't bother them, and for my preservation purposes they are good.

Things that grow underground can hang right out in full view and few here in the city or 'burbs will even recognize them. Sweet potatoes just look like lovely, lush foliage with some pretty morning glory flowers. (In fact, here, invariably morning glories sprout up among sweet potatoes.) Jerusalem artichokes? Ah, nice tall wildflowers. And did your thief happen to bring a shovel anyway?

If casual theft seems to be a problem, forcing the thief to bend or squat might help them decide to move along. Strawberries grown directly on the ground rather than in raised beds, cucumbers and tomatoes sprawled over the ground rather than trellised or caged. Bush beans rather than pole beans. Then there is always the options of sneaking clumps of edibles into an apparently ornamental garden-- for example tiny hot peppers on a diminutive plant planted between the daisies and daylilies (daylily that's another hiding in plain sight plant)

My neighbors told me that year after year they had trouble with their watermelons being stolen. They were grown on the public-facing edge of the garden behind a chain link fence, yet picking a single fruit would give the thief a big, quick reward. But once my neighbors started simply putting a brown cardboard box over the growing fruit, the theft stopped. The fruit was no longer visually advertising itself, and here in the city not a lot of people recognize a watermelon vine unless they see the fruit. So protecting it was just that easy.

After my winter squash started getting big this year, I left the grassy weeds to grow up with them and disguise the squash. Looks like a mess, an untended part of the garden, not like food at all. Plus, I get to be lazy!