Upfront payments are only partially about not getting ripped off. Their other functions include verifying that the potential client is ready to start their project and they have already allocated funds. It identifies potential clients in the "tire kicking" phase. The consultant's forecasts are likely to be more accurate and less based on wishful thinking.
1. Avoid getting ripped off by requiring upfront payment
2. Charge a rush fee for “I need this yesterday” requests
3. Upsell services by giving spectrum quotes
4. Filter our pathological customers by increasing your hourly rates