This was actually common in the early version, in which one of the many money glitch exploits involved selling off tiberium silos which somehow gave you way too much credits and a technician to boot. So you'd end up with armies of them to be used as cannon fodder.
Of course the GDI guard tower sell/stop trick gave you around the same amount of creds but also 3 minigunners a pop. Which you could either use en masse or sell off using the unit selling glitch.
Add the early version 250 cred NOD turrets and the AI's inability to deal with sandbags to that and I wonder if anyone played that game's single player campaign without cheating.(Though some of the Covert Operation missions were simply impossible if you didn't at least use the sandbags)