Are you sending $$$ out of the country??? Do you trust your source??? I know someone that regularly receives $5K+ in cash via Fed Ex domestically. The sender obviously thinks it's worth the risk of losing his $$$ in a lost package as opposed to risking getting caught via paper trail. If you're sending someone $1K, chances are they aren't going to rip you off if they think you'll be repeating biz. Ripping someone off once and getting a bad rep is hardly worth losing multiple repeat orders that will yield a much better profit over time.
Regardless, never send more $$$ than you can afford to lose and you're golden.