I guess it really depends on where you live and how careful you are (no super-late trips... no driving to out-of-the-way ATMs or on remote overpasses/underpasses)... I still don't know anyone who's been carnapped.

RE: Taxi issue. Probably a non-issue. It's actually easier to sell a car that can be converted into a taxi (puwede na ba ulit magka-bagong line sa secondhand?)... but I don't see the taxi issue affecting Corolla or Vios resale values.