How to efficiently break your code by using exceptions? Example 1: Pokemon exception catching

PokemonExceptionCatching.cs

using System;

namespace FunWithExceptions
{
    /*
     * 'Vindigator' is an imaginary 3rd-party library that contains
     * a lot of useful (if you're into the vindication business) APIs.
     */
    public static class Vindigator
    {
        /// <summary>
        /// Return true if the customer is a good customer, false otherwise.
        /// </summary>
        public static bool IsCustomerAGoodCustomer(Customer customer)
        {
            if (customer == null)
                throw new VindigatorInvalidCustomerException("Something is wrong with your customer!");

            if (customer.AmountOwed < 1000)
                return true;

            return false;
        }
    }

    public class VindigatorInvalidCustomerException : Exception
    {
        public VindigatorInvalidCustomerException(string message) : base(message)
        {}
    }

    public class Customer
    {
        public int Id { get; set; }
        public string Code { get; set; }
        public Decimal AmountOwed { get; set; }
    }

    public class VindicationReport
    {
        public Customer Customer { get; set; }
        public bool IsGoodCustomer { get; set; }
        public Decimal MoneyOwed { get; set; }    
    }

    public class ValuationRates
    {
        public Decimal PercentageFee { get; set; }
        public DateTime ValuationDate { get; set; }
    }

    public static class MyBusinessApp
    {
        public static VindicationReport GenerateVindicationReport(Customer customer, ValuationRates rates)
        {
            var report = new VindicationReport { Customer = customer };

            try
            {
                report.IsGoodCustomer = Vindigator.IsCustomerAGoodCustomer(report.Customer);

                if (report.IsGoodCustomer)
                    report.MoneyOwed = report.Customer.AmountOwed;
                else
                    report.MoneyOwed = report.Customer.AmountOwed + report.Customer.AmountOwed * rates.PercentageFee;
            }
            catch (Exception)
            {
                // [Richard] if we get an exception here, it means the customer is null!
                // Seems to happen when the main vindication job gets stuck (damn John!). Return a null report in that case.
                return null;
            }

            return report;
        }
    }
}