From: Rabbi Moshe Sofer
To: Rabbi Dovid Tzvi Villen
The Chasam Sofer addresses whether non-Jewish harvesting of wheat for shmurah matzah is valid, whether chasidim harvesting from others' fields face theft concerns, and whether wages may be paid for guarding items forbidden from benefit. He rules that only guarding from leavening requires lishmah—not harvesting.
Source: Shu"t Chasam Sofer OC §128