On our server, I noticed something "suspicious" too, except I immediately banned the user, and his family. Because what these people are doing is what I used to do on call of duty on the 360.
It's a lagswitch, or at the very least that's what it looks like.
User has a way of physically bottlenecking his network, digitally he is sound, so isn't kicked by the pingbscript, although their ping reaches over 9000. In doing this they can spam click, or in the case of the pic I'll post below, use a macro click, and they can sell the same Vic, multiple times in a super short window. I counted 120 of these striders, before I got to pissed to be bothered and started slamming digital heads in. Enjoy the pic, if you want more information let me know.
Also, pay attention to time stamp, vehicle I'd and money earned.