Is there any reason that property taxes couldn't be increased solely on homes without residents? It would at least encourage putting foreign owned homes on the rental market.
Residency tracking is hard. Actually, the city of Vancouver got permission from the provincial government to implement a vacant homes tax, but it's based on the home being unoccupied for a whole year. It probably won't work.
People would just hire someone or ask a relative to sign a lease and officially be "the resident" without actually having anyone live in the unit.