Ok im sure this is possible especially if your using process guard to hide processes and what not..so...
I know on lineage 2 there is a famous packet injecting program called Halpex that would allow you to inject items into the server saying you sold them (TO A VENDOR) ...now what if you did the same for wow...injected a packet saying for instance you sold the Singing crystal war axe or something yes you would lose gold but it would be cheaper then spending 2k gold on the ah you would only spend like 10 gold anyone good with packet sniffing and C or C++ could easly code it or just steal the source code from Halpex or Hlapex i forgot exactly how its spelled
PS: there was no proper thread to post this idea so i posted it in general moderator please move it to where you feal it properly fits