A garden with no fence gets trampled by people who swear they were just passing through.

Damage to something unprotected is usually not malicious, which is exactly why it keeps happening. People walk where there is nothing stopping them, and they do not register the cost, because it falls on you. Nothing gets fixed by hoping everyone will become more considerate on their own.

Put up the small marker before the trampling, not after. A stated time, a closed door, a simple sentence about what you are not doing. It is much easier to hold a line you drew calmly than to rebuild what walked through.