Oh yes, I do. I have been duped about 12 times during my 6 years as a Freelance Writer.
The amounts have ranged from $10 to $1600.
So, I do charge an advance. For small amounts below $100 or INR 5000/-, I charge a 100% upfront Payment.
For larger transactions I charge a 50% advance and the balance 50% before delivering the final set of articles.
For SEO services, the payment is 100% upfront depending on the contract period that you choose.
I hope that answers your queries.