Since parking is a limited and shrinking commodity, rules are needed. Rules need to be clearly communicated. Since parking rules can affect guests, signage at the community entrances needs to clearly describe the Parking Policy. The punishment should be consistent. Many rules fail when subject to multiple warnings and erratic enforcement.
Most folks are smart enough to understand why parking restrictions are needed and willingly comply.
For those that refuse to comply, towing works. Occasionally, the towing company will get overzealous or make a mistake. This is not a reason not to have the policy IF there is a real problem. The punishment should fit the crime. While towing may be excessive for some association, it may be entirely appropriate when local business customers use association parking or multiple vehicle residents are frequently using guest parking.