@struggler said:
The problem is not with a by law to vote out visitors parking spots but to get all to agree to a by law to tow cars parked in the visitors spots away at owners expense.
I totally agree with your sentiment but with half the owners ignoreing the parking bylaw you have no chance of getting a new bylaw passed to tow or clamp so you have to attack the problem from a different perspective.
My soloution is the only legal option open to you (as far as I know), you might be able to include multiple respondents or even the whole strata for ignoreing the parking bylaw. In QLD the Strata have a legal duty to enfore the bylaws and so you can take action against the strata but this is lacking in NSW.