if the source is legit you should have no problems. i think its the best way to actually do things leaves no paper trail at all, no western unions laying around, no e-gold accounts and so on.
make sure the source has been around is legit and knows how to operate worse thing is you will order some stuff send cash and never see anything and lose a few hundred bucks then you get over it and move on untill you find a source that is legit.Thats worst case i would say anyone thats been in this game for the last 7 years knows whats its about and has prob lost a few bucks in the process anything from not getting every item ordered to not seeing anything at all.
I malied a source cash a few years back then read on the boards he got popped i was glad not to see anything get mailed to my house if i had did western union or egold they could have gotten a paper trail and followed it.